Part 2

This species is typically narrower than _A. lustrica_ Pils., with a smaller aperture and shorter whorls; but it is chiefly distinguished by the more convex whorls (deeper suture), and the rounded instead of angular posterior end of the aperture. In _Paludestrina nickliniana_ the last whorl is much longer. Possibly it may be a subspecies of _lustrica_, yet it has so distinct an appearance that a special name seems desirable. There are also wider examples, which still differ from _lustrica_ by the deeper suture and aperture.

NEW GENERA AND SPECIES OF CENTRAL AMERICAN NAIADES.

BY L. S. FRIERSON.

In 1893 Messrs Crosse and Fischer divided the Mexican Naiades into quite a number of sections, to which they assigned names. Almost simultaneously (in 1900) von Martens and C. T. Simpson, in treating the Central American Naiades, accepted some of these sections of Crosse and Fischer, raising them to generic or subgeneric rank. Because of paucity of material, considerable diversity of opinion concerning the specific identity of several species may be noted in the works of these authors. Furthermore, their work of classification being done independently and from different points of view, the same species was sometimes placed by them in different genera.

Thanks to the arduous labors of A. A. Hinkley, who has again and again enriched our cabinets with material and data from these tropical countries, we are enabled to offer the following suggestions concerning some of the genera of these shells, and also the description of an unpublished species.

NEPHRONAIAS. This genus has for its type the _Unio plicatulus_, Küster, a species identified by von Martens as belonging to the Lampsiline shells, as _aztecorum_. Mr. Simpson however believed it to be nearly allied to the _persulcatus_, a markedly Unioid shell. In this the writer follows Mr. Simpson.

The genus _Nephronaias_ as constituted by Mr. Simpson embraces two quite distinct groups, divisible as follows.

_Nephronaias_ (_s. s._) embraces _plicatulus_, _persulcatus_, _melleus_, _dysoni_, _ortmanni_, _ravistellus_, etc. Ample material of these two latter species show that they are anatomically very closely allied to _Elliptio_. There is no sexual difference of shape, and the gill is gravid in its whole length. _Nephronaias_ differs from _Elliptio_ in its sulcated disc, in its beak sculpturing, etc.

Included in _Nephronaias_ by Simpson are, however, shells of a totally different type, such as _medellinus_, _gundlachi_, _sapotalensis_, etc. These latter are sexually dimorphic, smoother, more generally rayed, and the gravid uterus is of Lampsiline type.

The position of the dorsal scars within the beak cavities is different, in the examples of the pseudo _Nephronaias_ seen by the writer. _Nephronaias_ (_s. s._) possesses an (accessory?) adductor scar attached to the frontal portion of the cardinal teeth, which is either absent or obsoletely marked in the second assemblage. For this latter group the writer, therefore, proposes to use the generic term of _Actinonaias_ Crosse and Fischer, 1893, type _U. sapotalensis_ Lea. The female of this species has been described by Dr. Ortmann (1912). _Actinonaias_ embraces, besides the type, _medellinus_, _gundlachi_, (accepting Simpson’s interpretation of this latter species), and others.

PSORONAIAS, Crosse and Fischer (1893). This group of remarkable shells, embracing _crocodilarum_, _psoricus_, _semigranosus_, etc., was provisionally treated by Simpson as a group of _Elliptio_, but their remarkable sculpturing, and the deep beak cavities of some of their species, led him to observe that it was possible that the group should, after all, be placed in _Quadrula_.

I follow von Martens, in giving generic rank as above to the group. The type is _Unio psoricus_. To this genus we are enabled to add a species hitherto undescribed, under the name of

PSORONAIAS KUXENSIS, n. sp., PI. VII, figs. 1, 2.

Shell small, compressed, rough, brown, biangular. Length 50, height 30, diam. 17 mm.

Shell hyperbolically rounded before, the extreme frontal point below the centre. Dorsum slightly arched, descending behind the ligament to the widely biangular posterior; the upper angle of which is midway the height, the lower angle very little above the base, which is nearly straight. The beaks are small, low, acute, approximate; and _apparently_, concentrically ridged. Epidermis dark brown (olivaceous and obsoletely rayed in the young), rough, the lines of growth numerous and well impressed. The discs are covered with fine pustulations, more pustular in front, biradially linear behind. The post ridge is low, but distinctly double, making the shell biangulate behind. The teeth are double in the left valve, single in the right. The cardinals are deeply sulcate and stout. Laterals slightly curved or nearly straight, separated by an interdentum. Nacre purple, beak cavities rather deep. Dorsal scars numerous, extending in a row from above the centre of the cavity down and forward upon the base of the cardinal teeth. Three well impressed muscle scars in front, two behind, the latter almost confluent. Habitat, Kux Creek, Chama, Guatemala. Collected by Mr. A. A. Hinkley, Feb. 6, 1917. A few dead specimens were obtained on the bank of the Isaibha River (Chama) of which the Kux Creek is a tributary. Type in Academy Natural Sciences. Cotypes in collection of A. A. Hinkley, the author and U. S. N. Museum.

I place this species in _Psoronaias_ Crosse and Fischer, type _U. psoricus_, because of its evident relationship to _crocodilarum_, and _distinctus_, differing mainly from the latter in size and degree of inflation, being much inferior in both respects to _distinctus_.

ON THE RATE OF GROWTH OF POND UNIOS.

BY L. S. FRIERSON.

During the latter part of March 1916, the writer, for the purpose of constructing a fish pond, excavated a barrow-pit near the bank of a small creek, about ten feet wide, and at the time nearly dry. The barrow-pit was perhaps one hundred feet long, fifty feet wide and three feet deep. Early in April, 1916, the pit became full of water, overflowing from the adjacent creek, and together with two subsequent overflows, supplemented with seepage from the newly constructed fish pond, the pit remained more or less full of water, until May 25, 1917, when it was drained by a ditch into the nearby creek. From the dried bottom of this pit some thirty Unios were picked up by the writer. Ten of these were _Unio tetralasmus_ Say, and the rest were _T. texasensis_ Lea. All the specimens were of remarkably uniform size and appearance. The _texasensis_ being about one and a half inches, and the _tetralasmus_ two and a half inches long. Exact dimensions of a _texasensis_: length 43, height 24, diam. 16 mm.; of _tetralasmus_ 75, 40, and 25 mm.

Both of these species had attained puberty. A female _texasensis_ had its gills fairly full of young glochidia. A _tetralasmus_ had several (three or four) ovisacs with a few (remaining) glochidia. In assigning an age to these shells it is quite sure that the _tetralasmus_ discharges its glochidia in March and early April, so that when picked up on May 25, these shells were just about fourteen months old, from the date of discharge from their mother’s gills.

In the case of the _texasensis_ (which spawns somewhat later) it is possible that these were dropped by fish of which, at least six species obtained access to the pit on May 7, 1916 (on which date an overflow occurred), thus making about thirteen months. At any rate the maximum age of either species is fourteen months from their mother’s ovisacs. One of the _U. tetralasmus_ is shown of natural size in Pl. VII, fig. 4.

Another observation concerning pond mussels might here prove of interest. A large pond was cut into two by a railroad embankment, a culvert preserving the level and providing communication between the two. In the lower and larger pond a half-bushel of Yonkapin (_Nelumbium luteum_) seed was sown. It was six years before these seeds germinated. These plants, during the summer, cover the entire surface of the pond with their broad peltate leaves. In this pond the writer planted a colony of a dozen _Anodonta grandis_. Several years after, taking advantage of extreme low water, the writer made a careful survey of these twin ponds, with the result that hundreds of Anodons could be found in the upper pond, but not a single one was found in the lower pond. Either the shade killed the young shells, or else the glochidia-laden fish avoided the shade of the lotus plants and congregated in the upper pond (there are no Nelumbii in the upper pond). Is not this avoidance of shade a reason for the paucity of unios in the tropics?

A NEW SOUTH AFRICAN NESOPUPA.

BY H. A. PILSBRY.

NESOPUPA FARQUHARI, n. sp.

Among Pupillidae sent by Mr. J. Farquhar there is a new species from Grahamstown which may be defined by comparison with _Nesopupa griqualandica_ (Melv. and Pons.).[5] The new form is ovate, of about the size of the other species, which it resembles in sculpture and in the lamellae of the parietal wall and columella. The two palatal plicae are subequal, the upper emerging to the lip, the lower one also long, reaching to the inner edge of the peristome. There is a very small nodule on the base of the columella. In _griqualandica_ the lower palatal plica is short and very deeply immersed and there is a distinct though small basal plica within the base, in front of the lower palatal plica. In _griqualandica_ there is a deep sulcus outside, over the upper palatal plica, and a flattening or short groove over the lower palatal; but in _farquhari_ the sulcus is far less impressed except quite close to the lip. The color is reddish brown. Length 1.65, diam. 0.9 mm.

Mr. Burnup’s figure 9, in Melvill and Ponsonby’s Revision,[6] may perhaps represent this species, while their description in the same paper appears to comprise both _griqualandica_ and _farquhari_, though chiefly relating to the former. Their pl. I, figs. 8 and 10 represent _griqualandica_. The new form is named in honor of one of the most successful South-African collectors. It will be figured in the Manual of Conchology.

A NEW GUNDLACHIA FROM GUATEMALA.

BY BRYANT WALKER.

GUNDLACHIA HINKLEYI, n. sp., Pl. I, figs. 10‒16; Pl. III, fig. 1.

Shell subovate, being much wider posteriorly, the anterior margin rather shortly rounded, the right margin nearly rectilinear, but somewhat diverging anteriorly, the left margin obliquely expanded and broadly rounded, anterior margin wider and much more curved than the posterior; apex very excentric, depressed and decidedly turned toward the right side, bluntly rounded, smooth except for a few concentric wrinkles; color a very pale corneous, nearly pure white; lines of growth rather strong and irregular; anterior slope with strong radial striæ originating below the septate growth and extending to the anterior margin, similar striæ appear on the left lateral slope, but are scarcely, if at all, visible on the right slope; the septate portion of the shell is small in comparison with the adult expansion, it is narrow and the posterior portion covered by the septum is free from and projects over, but scarcely beyond, the posterior margin of the adult aperture; the first growth of the shell from the septate form is continued on the sides in a nearly direct continuation of the lateral slopes of the septate shell for some little distance, the anterior slope of this stage is also a continuation of the anterior slope of the septate stage but owing to the oblique position assumed by the septate shell is at first somewhat convex, as viewed laterally, later as the side slopes begin to expand, the anterior slope is continued in a nearly straight line to the margin; the left lateral slope of the adult shell below the secondary constriction is concave at first, becoming nearly straight toward the margin; the right lateral slope is less concave above and straighter and more oblique than the left; owing to the small size of the septum and consequent large aperture of the septate shell and the narrow first growth of the adult shell there is no distinct aperture to the septate portion visible in the adult shell from below, the whole interior of the adult shell appears to pass, practically unconstricted, directly into the septate portion; the posterior margin of the adult shell narrow and somewhat abruptly expanded and reflected.

Length 5.5; width 3.75; alt. 1.75 mm.

The septate shell is oblong, the sides being nearly parallel, but slightly expanding anteriorly, the right slightly convex and the left slightly concave; the posterior margin is regularly rounded; the anterior more broadly rounded; the apex depressed, bluntly rounded, excentric, reaching nearly to the right margin, smooth except for slight concentric wrinkles, lines of growth fine and regular; the anterior slope is slightly convex; the very short posterior slope below the projecting apex to the line of the septum is straight and oblique; the right lateral slope is steep and nearly straight, the left slope very convex; the septum is very short, being less than half of the length of the septate shell, convex on its lower surface, the margin is very short, being less than half of the length of the septate shell, convex on its lower surface, the margin is very concave and on the right side, extends further forward than it does on left, there does not seem to be the distinct thickening of the margin so noticeable in other species; aperture much larger than in any other species yet described.

Length 2; width 1.5; alt. .75 mm.

Type (43455 Coll. Walker) from the Maya Farm, Quirigua, Guatemala, collected by A. A. Hinkley. Cotypes in the collection of Mr. Hinkley.

This fine species is the first from either Central or South America, of which both the septate and adult forms are known.

It differs from all other described species except _crepidulina_ Guppy in the small size of the septum and the consequent difference in the position of the aperture of the septate stage in the adult shell. The septum in the specimen figured appears very like the incomplete septum in the North American species, but as the three adult specimens before me are exactly alike in the position of the septate shell, this would seem to be the normal condition in this species. The specimen figured, which is 3.25 mm. in length, has apparently slightly passed the septate stage and begun the growth of the constricted portion of the adult shell and shows the beginnings of the radial striæ.

With the Gundlachias was associated a species of _Lævapex_, very like the _excentricus_ Morelet. Whether it has any closer relations with the _Gundlachia_ remains to be determined as the radula has not yet been examined. While the general aspect of the two species, if such they be, is very similar, the _Lævapex_ has a very much more acute apex than the _Gundlachia_.

As shown by the figure, the radula of this species is quite typical of the genus.

A LIST OF SHELLS FROM THE EAST COAST OF FLORIDA.

BY BRYANT WALKER.

The late Dr. Charles A. Davis, the well known peat-expert of the U. S. Bureau of Mines, in addition to his special acquirements in geology and botany, was a good all-round zoologist and had a lively and unaffected interest in the work that any of his friends might be carrying on in that department. It was his kindly habit in his travels about the country to preserve any specimens that he came across that seemed to him likely to be of interest to any of his zoological friends. It will be remembered that the conchologists owe to him the rediscovery of the long lost _Planorbis multivolvis_ Case, (NAUT., XXI, p. 16), and also the little _Lymnæa davisi_ Walker, (NAUT. XXII, p. 17), which bears his name.

In the spring of 1911 Dr. Davis’ professional duties took him to Florida and while there he collected quite a number of samples of “drift,” which in due time came into my possession. Several of the localities represented in the collection, such as Miami and St. Augustine, have already been reported upon by previous collectors and there seems to be no occasion to duplicate their work, but quite a number of the places visited by Dr. Davis have not been covered by any of the previous collectors in Florida and a record of the species found by him seems worthy of publication as a contribution to the distribution of the Mollusca along the east coast of the state.

I am indebted to Dr. George H. Clapp for the identification of the Gastrocoptas and Vertigos.

The list of localities and species represented in the collection is as follows:

MARSHES NEAR CHESTER SHOALS.

_Euglandina rosea_ Fér. _Polygyra cereolus carpenteriana_ Bld. _Zonitoides minuscula_ (Binn.). _Zonitoides minuscula alachuana_ (Dall). _Vitrea dalliana_ (‘Simpson’ Pils.). _Pupoides modicus_ (Pfr.). _Gastrocopta rupicola_ (Say). _Gastrocopta pellucida hordeacella_ (Pils.). _Gastrocopta tappaniana_ (C. B. Ads.)? _Gastrocopta pentodon_ (Say). _Vertigo milium_ (Gld.). _Melampus coffeus_ (L.). _Detracia bulloides_ (Mont.). _Chrondropoma dentatum_ (Say). _Plecotrema cubense_ (Pfr.). _Blauneria heteroclita_ (Mont.). _Microtralia minuscula_ (Dall). _Truncatella clathrus_ Lowe. _Truncatella caribæensis pulchella_ Pfr. _Truncatella bilabiata_ Pfr. _Littoridina monroensis_ (Ffld.).

_Paludestrina?_ sp.? A single specimen that I can not approximate to any of the described species.

This is the first record, I believe, for _Plecotrema cubense_ from the mainland of Florida. Originally described from Cuba, it was listed from the Bermudas by Dr. Pilsbry in 1900, (Trans. Conn. Acad., X, p. 504, pl. lxii, fig. 11), and there figured by him for the first time. Both he and Mr. John B. Henderson inform me that they have collected it on several of the Keys and I am indebted to both of them for the opportunity of comparing my specimen with theirs.

CHESTER SHOALS REFUGE STATION.

_Euglandina rosea_ (Fer.). _Polygyra auriculata_ (Pfr.). _Polygyra uvulifera_ (Shutt.). _Polygyra cereolus_ (Mühlf.). _Polygyra cereolus carpenteriana_ (Bld.). _Polygyra cereolus septemvolva_ Say. _Polygyra cereolus volvoxis_ (Pfr.). _Praticolella jejuna_ (Say.). _Melampus coffeus_ (L.). _Detracia bulloides_ (Mont.) _Lymnaea humilis_ Say. _Physa cubensis_ Pfr. _Planorbis tumidus_ Pfr. _Planorbis alabamensis_ Pils. _Chrondropoma dentatum_ (Say). _Truncatella bilabiata_ Pfr. _Truncatella clathrus_ Lowe. _Littoridina monroensis_ (Ffld.).

BETWEEN CHESTER SHOALS AND CAPE CANAVERAL.

_Polygyra cereolus_ (Muhlf.). _Polygyra cereolus carpenteriana_ (Bld.). _Polygyra cereolus volvoxis_ (Pfr.). _Polygyra uvulifera_ (Shutt.). _Zonitoides minuscula_ (Binn.). _Pupoides modicus_ (Pfr.). _Gastrocopta pentodon_ (Say). _Gastrocopta pellucida hordeacella_ (Pils.). _Gastrocopta rupicola_ (Say). _Melampus coffeus_ (L.). _Detracia bulloides_ (Mont.). _Blauneria heteroclita_ (Mont.). _Chrondropoma dentatum_ (Say). _Truncatella bilabiata_ Pfr. _Truncatella clathrus_ Lowe. _Truncatella caribæensis pulchella_ Pfr.

_Amnicola._ sp.? A single immature specimen.

CANAVERAL P. O.

_Euglandina rosea_ (Fer.). _Polygyra cereolus septemvolva_ Say. _Polygyra cereolus volvoxis_ (Pfr.). _Polygyra cereolus carpenteriana_ (Bld.). _Pupoides modicus_ (Pfr.). _Helicina orbiculata_ Say.

EAU GALLIE.

_Polygyra cereolus septemvolva_ Say. _Polygyra cereolus volvoxis_ (Pfr.). _Polygyra uvulifera_ (Shutt.). _Physa cubensis_ Pfr. _Helicina orbiculata_ Say var.

ISLAND OF EAU GALLIE.

_Polygyra uvulifera_ (Shutt.). _Praticolella jejuna_ (Say). _Lymnaea humilis_ Say. _Physa cubensis_ Pfr.

PALM BEACH.

_Euglandina rosea_ (Fer.). _Polygyra auriculata_ Say. _Polygyra cereolus carpenteriana_ (Bid.). _Strobilops floridana_ Pils. _Strobilops hubbardi_ (Brown). _Pupoides modicus_ (Pfr.). _Gastrocopta contracta_ (Say). _Gastrocopta rupicola_ Say. _Gastrocopta pellucida hordeacella_ (Pils.). _Gastrocopta pentodon_ (Say). _Vertigo milium_ (Gld.). _Vitrea dalliana_ (‘Simp.’ Pils.). _Vitrea indentata_ (Say). _Zonitoides arborea_ (Say). _Zonitoides minuscula_ (Binn.). _Zonitoides minuscula alachuana_ (Dall). _Guppya gundlachi_ (Pfr.). _Thysanophora granum_ (Streb.). _Physa cubensis_ Pfr. _Helicina orbiculata_ Say.

LONG KEY.

_Euglandina rosea_ (Fer.). _Polygyra cereolus_ (Mühlf.). _Polygyra cereolus carpenteriana_ (Bid.). _Strophia incanum_ (Binn.). _Pupoides modicus_ (Pfr.). _Gastrocopta pentodon_ (Say). _Gastrocopta rupicola_ (Say)? _Gastrocopta pellucida hordeacella_ (Pils.). _Gastrocopta pellucida hordeacella_ (Pils.) var. Small form. _Thysanophora incrustata_ (Gld.). _Thysanophora granum_ (Streb.). _Thysanophora dioscoricola_ (Guppy). _Guppya gundlachi_ (Pfr.). _Varicella gracillima floridana_ Pils. _Succinea campestris_ Say? _Melampus coffeus_ (L.). _Detracia bulloides_ (Mont.). _Microtralia minuscula_ (Ball). _Lymnæa columella_ Say. _Physa cubensis_ Pfr. _Helicina tantilla_ Pils. _Chrondropoma dentatum_ (Say). _Truncatella caribæensis_ Sby.; Rve. _Truncatella caribæensis pulchella_ Pfr. _Truncatella clathrus_ Lowe. _Truncatella bilabiata_ Pfr. _Littoridina monroensis_ (Ffld.).

_Amnicola. sp?_ A single specimen of a very small, globose form that may be an n. sp. Alt. 1 mm.

COLLECTING IN DIGBY, NOVA SCOTIA.

BY LILLIAN DYER THOMPSON.

While traveling through Nova Scotia and New Brunswick last summer, we stayed for about six weeks at Digby, N. S. Digby is about 200 miles northeast of Boston, and is situated near the Bay of Fundy, opposite St. John, N. B. The town is located on the southeast shore of the Annapolis Basin,—a sheet of water about twenty miles long and ten miles wide. This basin is connected with the Bay of Fundy by a channel about three-fourths of a mile wide at its greatest width. This channel, known as Digby Gap, is noted for its rapid tides,—the rate of flow through the Gap being about eight miles an hour. The tide fall at Digby is thirty feet. The shores of the Basin are sandy, with the exception of the two rocky promontories on each side of the Gap; the one which is nearest to Digby being Point Prim. The town is on a small peninsula on either side of which are two inlets of the Annapolis Basin, known as the Racquet, on the west, and the Jacquet, on the east of Digby proper. On the ebb tide these are almost dry, exposing long mud flats.

There is one island in the Basin, about opposite the Gap and at the mouth of Bear River, called Bear Island. From this a long bar extends, called Bear Island Bar, which is covered to a depth of about six feet at low water, and is covered with eelgrass.

Near the Yacht Club pier were found many _Polinices heros_, and their red-brown “sand-collars.” In the Jacquet were many _Litorina littorea_ and _Litorina rudis_. On the exposed beach, nearer the town, we found _Mytilus edulis_. On the rocks, in the Racquet, we found _Thais lapillus_ and a host of _Acmaea testudinalis_ ranging in size from one-eighth of an inch to about an inch in diameter. In the mud, at the base of the rocks, were a multitude of _Buccinum undatum_, _Neptunea decemcostata_, ranging in size from one-eighth of an inch to about an inch in diameter. In the mud, at the base of the rocks, were a multitude of _Buccinum undatum_, _Neptunea decemcostata_, and _Colus stimpsoni_, all alive and half-buried. Some dead specimens of _Aporrhais occidentalis_ were also found, five of them being full-grown.

On the suggestion of Capt. Danforth, we constructed a dredge, and endeavored to dredge Bear Island Bar from his motor-boat. Here we found quantities of _Lacuna vincta_, _Alectrion obsoleta_, _Cylichna alba_, and two _Polinices triseriata_.