Part 72

Fig. 1 _a_, Tetraclita porosa, _var._ communis. 1 _b_, " " " rubescens. 1 _c_, " " " nigrescens. 1 _d_, " " " elegans. 1 _e_, " " " communis, young, with radii developed. 1 _f_, " " " patellaris. 1 _g_, " " basal edge of wall of shell. 1 _h_, " " basal edge of wall of shell, _var._ elegans, showing also the structure of one of the rudimentary radii or sutures. 1 _i_, " " internal view of scutum; 1 _k_, do. of tergum; 1 _l_, do. of scutum, _var._; 1 _m_, do. of tergum, _var._ 2 _a_, Tetraclita serrata; 2 _b_, portion of external surface of wall, low down, near basis; 2 _c_ and 2 _d_, scutum and tergum, internal views. 3 _a_, Tetraclita rosea, scutum; 3 _b_, tergum; 3 _c_, whole shell; 3 _d_, basal edge of wall of shell.

PLATE 11.

_Genera_--TETRACLITA AND ELMINIUS.

Fig. 1 _a_, Tetraclita purpurascens, _var._ with surface disintegrated, and with the sutures united and obliterated. 1 _b_, Tetraclita purpurascens, _var._ well preserved, with the radii developed; 1 _c_ and 1 _d_, _var._ scutum and tergum, internal views. 2 _a_, Tetraclita costata; 2 _b_ and 2 _c_, scutum and tergum. 3 _a_, Tetraclita vitiata; 3 _b_, basal edge of portion of wall; 3 _c_ and 3 _d_, scutum and tergum, internal views of; 3 _e_, tergum, internal view, _var._ 4 _a_, Tetraclita cœrulescens; 4 _b_, scutum and tergum united, external view; 4 _c_ and 4 _d_, scutum and tergum, internal views. 5 _a_, Tetraclita radiata; 5 _b_, scutum and tergum united, external view; 5 _c_ and 5 _d_, scutum and tergum, internal views. 6 _a_, Elminius Kingii; 6 _b_ and 6 _c_, scutum and tergum, internal views of; 6 _d_, tergum, _var._ external view of; 6 _e_, tergum, another _var._ internal view of.

PLATE 12.

_Genera_--ELMINIUS AND PYRGOMA.

Fig. 1 _a_, Elminius modestus; 1 _b_, scutum, internal view; 1 _c_, tergum, internal view; 1 _d_, do., tergum, _var._; 1 _e_, do., tergum, _var._ 2 _a_, Elminius plicatus; 2 _b_, basal edge of portion of wall of shell; 2 _c_ and 2 _d_, scutum and tergum, internal views of; 2 _e_ and 2 _f_, scutum and tergum, internal views of, _var._ 3, Elminius simplex; shell. 4 _a_, Pyrgoma Anglicum; 4 _b_ and 4 _c_, scutum and tergum, internal views. 5 _a_, Pyrgoma cancellatum, shell, seen from above; 5 _b_, shell seen on the under side; 5 _c_ and 5 _d_, scutum and tergum, external views; 5 _e_ and 5 _f_, scutum and tergum, internal views of. 6, Pyrgoma Stokesii, shell imbedded in coral. 7 _a_, Pyrgoma conjugatum, shell, external view of; 7 _b_, scutum and tergum, calcified together, seen from the outside; 7 _c_, do., internal view of.

PLATE 13.

_Genera_--PYRGOMA AND CREUSIA.

Fig. 1 _a_, Pyrgoma grande; 1 _b_, scutum and tergum, calcified together, external view of; 1 _c_, scutum and tergum, internal view of; 1 _d_, the two scuta and terga, external view, seen from above, having their natural position, when closed. 2 _a_, Pyrgoma milleporæ, shell viewed from above; 2 _b_, internal view of, showing the sheath; 2 _c_, scutum and tergum, united, external view of; 2 _d_, scutum, _var._ external view of; 2 _e_, scutum, internal view of; 2 _f_, tergum, internal view of. 3 _a_, Pyrgoma dentatum shell, external view of; 3 _b_, scutum, _var._ 1, external view of; 3 _c_, tergum, _var._ 1, external view of; 3 _d_, tergum, _var._ 2, external view of; 3 _e_, scutum, _var._ 3, external view of; 3 _f_, tergum, _var._ 3, external view of; 3 _g_, scutum and tergum, _var._ 1, joined together, internal view of. 4 _a_, Pyrgoma crenatum, scutum, external view of, showing the great depending adductor plate and large occludent ledge; 4 _b_, external view of. 5 _a_, Pyrgoma monticulariæ, external view of; 5 _b_, another specimen, internal view of; 5 _c_, another specimen, external view of; 5 _d_, portion of circumference of shell, viewed externally, much magnified, showing the outer lamina, and the irregular, longitudinal septa; 5 _e_, another specimen of the same, with the longitudinal septa more regular; 5 _f_, scutum and tergum completely calcified together, external view of. 6 _a_, Creusia spinulosa, shell, seen from above. 6 _b_, 6 _c_, Creusia spinulosa, _var._ 1, scutum and tergum, internal view of; 6 _d_, scutum and tergum, joined together, external view of. 6 _e_, 6 _f_, 6 _g_, Creusia spinulosa, _var._ 2, 6 _e_, scutum, internal view; 6 _f_, tergum, internal view of; 6 _g_, tergum, of another specimen, internal view of. 6 _h_, Creusia spinulosa, _var._ 3, scutum and tergum joined together, external view of.

PLATE 14.

_Genera_--CREUSIA AND CHELONOBIA.

Fig. 6 _i_, 6 _k_, 6 _l_, Creusia spinulosa, _var._ 4, 6 _i_, tergum, external view; 6 _k_, the same, from another individual; 6 _l_, the same, internal view. 6 _m_, Creusia spinulosa, _var._ 5, tergum, external view. 6 _n_, 6_o_, 6_p_, 6_q_, Creusia spinulosa, _var._ 6, 6 _n_, scutum, external view of; 6 _o_, tergum of same individual, external view of; 6 _p_, scutum of another individual, external view of; 6 _q_, tergum of latter, external view of. 6 _r_, Creusia spinulosa, _var._ 7, scutum, internal view of. 6 _s_, Creusia spinulosa, _var._ 9, scutum and tergum, calcified together, external view. 6 _t_, Creusia spinulosa, _var._ 10, scutum and tergum, calcified together, external view. 6 _U_, Creusia spinulosa, _var._ 11, shell seen from above; 6 _u_, scutum and tergum, calcified together, external view.

Fig. 1 _a_, Chelonobia testudinaria, shell seen from above; a specimen has been chosen, with some of the radii smooth, and others more or less notched; 1 _b_, scutum, internal view of; 1 _c_, tergum, internal view of; 1 _d_, scutum and tergum, joined together, external view of. 2, Chelonobia caretta, shell seen from above. 3 _a_, Chelonobia patula, shell seen from above; 3 _b_, tergum, external view of. 4, Carina of Chelonobia patula, seen from within; _a a_, outer lamina of wall, joined by the longitudinal septa to _b_, the inner lamina; _e c e_, sheath, descending to the base of shell, with the middle part largely hollowed out; the upper part of the sheath, above _d d_, is transversely marked by the lines of attachment of the opercular membrane; _d_, _d_, alæ. 5, View of the edge of the radius of the rostrum of Chelonobia testudinaria. _a_, _a_, inner portion of radius. _b_, thick outer lamina of the radius, transversely pitted; beneath this pitted portion, which forms only the outer surface of the radius, and distinct from the inner portion _a_, the arborescent and dentated sutural edges of this outer lamina are seen. _c_, outer lamina of wall of compartment. _d_, the exterior septum, connecting the outer lamina of the wall to the inner lamina; the basal edge of the inner lamina of the wall is seen beneath and without the lower end of the inner portion (_a_) of the radius.

PLATE 15.

_Genera_--CHELONOBIA AND CORONULA.

Fig. 1, Transverse section of shell of Chelonobia testudinaria. B A B, Compound rostrum: A being the true rostrum. B B, the rostro-lateral compartments, which normally, in the Balaninæ, are quite confounded with the true rostrum: the sutures separating these three compartments are not continued through the outer lamina. C, left-hand lateral compartment. D, left-hand carino-lateral compartment. E, carina. S S, Sutures, six in number, separating the six compartments. _a_, outer lamina of wall of compartment, whence the radiating, longitudinal septa (left unshaded) arise, and at the opposite end blend into the indistinct inner lamina, viz. _b_, (see fig. 4, in last plate.) _c′_, sheath. _d_, ala, forming, as usual, part of the sheath. _e_, inner portion of the radius. _f_, _f_, outer lamina of the radius (see _b_, in fig. 5, in last plate), of great thickness, and externally deeply pitted;--the sharp ridges between the pits, produce in the section the points, such as that marked by the outer _f_. 2, Coronula balænaris, shell seen from above. 2 _a_, " " section of one of the transverse circumferential loops, formed by the folded wall of a compartment. The wall itself is formed of an outer and inner lamina, with longitudinal septa. The internal surfaces of the loop-part are connected by special shelly plates or longitudinal septa. 2 _b_, " " scutum and tergum united together by the opercular membrane (with horny ridges), seen from the inner side. 3, Coronula diadema, shell, seen from the outside; 3 _a_, scutum and tergum joined together by the opercular membrane, seen from the outside; 3 _b_, scutum cleaned and enlarged, seen from the inside. 4, Section, in a vertical plane, through the skin of a whale, on which a _Coronula diadema_ had been attached, but has been wholly removed: the two curved, horn-like projections occupied two of the eighteen cavities on the under side of the shell, formed by the folded walls: the blacker part is the epidermis; the lighter part is the yellowish fibrous tissue of the skin under the epidermis. 5, Coronula reginæ, shell seen from the outside. 6, Coronula barbara, internal view of the basal margin and inside of one of the compartments, exhibiting the circumferential transversely looped ends of the folds of the wall, with the inner surface transversely wrinkled. 7-9, diagrams, showing how one of the circumferential transverse loops of the wall becomes divided into two transverse loops, thus giving rise to another fold in the wall. 10, diagrams, showing how the wall of the young shell in Coronula, from being (_a_) simply sinuous, becomes deeply folded (_b_); the folds lastly (_c_) expanding transversely at their ends, thus giving rise to the circumferential transverse loops, as in fig. 7.

PLATE 16.

_Genus_--CORONULA.

Fig. 1, rostrum, viewed from the inner side, of _Coronula diadema_. _a_, sheath, marked transversely in the upper part by the attachment of the opercular membrane. _b_, furrow on each side of (_a_), receiving the edges of the thick alæ of the adjoining lateral compartments. _c′′_, special plate, on which the alæ on their outer sides rest. _d_, radius, on the edge it may be just seen to consist of an outer layer (the normal radius), and a much thicker inner part (the pseudo or complementary radius) formed of oblique denticulated septa. _e e′ e′′_, basal edge of wall, which from its commencement at _e_, or _e′′_ can be followed, folding up to near the basal edge of the sheath, to its termination at _e′′_ or _e_. _f_, serrated lines of junction between the folds of the wall. 2, Lateral compartment of _C. diadema_, seen laterally, on a smaller scale than last fig., but taken from the same shell; letters of reference the same: this figure, if the ala _a′_ were removed, would do for a lateral view of the rostrum, or fig. 1. _a_, sheath, much foreshortened. _a′_, ala (therefore also part of sheath), and the edge of which fits into _b_ of fig. 1. _b_, furrow receiving edge of ala of the adjoining carino-lateral compartment. _c′′_, special plate, seen edgeways. _d_, radius, the division into two parts, viz., the thin outer normal radius, and the under pseudo or complementary radius here shown (rather exaggerated) plainer than in fig. 1. _e_, basal edge of wall; to the right hand the three folds at their inner ends are seen obliquely, one behind the other: these are seen directly in front in fig. 1. 3, lateral compartment of _C. balænaris_, seen laterally; letters of reference the same as in last fig., but _c′′_ not introduced for this plate is barely developed, and only in the lower part, and is attached to the radius: _g g_ points where fresh folds have been formed in the walls along the lines of suture, as may be seen in the outline of the wall in fig. 5. 4, lateral compartment of _C. reginæ_, seen laterally; letters of reference the same as in the last two figures. 5, Coronula balænaris, outline of the basal margin of the folded walls: _s_, _s_, the six sutures. The wall can be continuously followed from one end of a suture to the next suture. 6, Coronula diadema; small portion of the external surface of the wall, close to the basal edge, highly magnified; _a_, outer lamina, not extending down to the basal edge; _b_, inner lamina; _c_, projecting longitudinal septa. 7, Coronula diadema; transverse section through the upper part of the shell, showing the rostrum and the two adjoining lateral compartments (and the alæ of the carino-lateral compartments), all supposed to be a little separated from each other, so that the sutures, _s s_, are shown by white lines. A A A, rostrum. C C, lateral compartments. D D, carino-lateral compartments, of which only the alæ (_a′_) are shown. Of the letters in italics, those which occur in figs. 1, 2, 3, 4, 5, refer all to the same parts, viz.:-- _a_, sheath, continuous with (_a′_) the alæ, where such occur. _c′′_, special plate on which the alæ rest. _d_, radius, divided into a thin outer normal radius, and the inner complementary portion, the latter shaded by convex lines of growth. _d′_ is a special tube (seen only as a black dot) for a thread of corium. _e_, folded walls. _f_, junction of the folded walls (see _f_, in fig. 1) leading into the cavities (_f′_) open beneath, and filled up by the epidermis (see Pl. 15, fig. 4) of the whale. _h_, inside of the transverse loops of wall, occupied by corium: in the enlarged section of a loop, in C. balænaris, in Pl. 15, fig. 2 _a_, the opposed sides are seen to be connected by shelly longitudinal plates. _v_, cavity occupied by the ovarian tubes and cæca.

PLATE 17.

_Genera_--PLATYLEPAS, TUBICINELLA, AND XENOBALANUS.

Fig. 1 _a_, Platylepas bissexlobata, shell of, viewed from the under side; A, rostrum; B, lateral compartment; C, carino-lateral compartment; E, carina. These letters are placed opposite the inward folds of each compartment forming the midribs. 1 _b_, Platylepas bissexlobata, shell of, viewed externally. 1 _c_, " " scutum and tergum, viewed externally and separated. 1 _d_, " " lateral compartment, viewed from the inside, showing the inward folded wall or midrib; _a′_, ala; _d_, radius. 2 _a_, Platylepas decorata, shell, viewed externally; A, rostrum; B, lateral compartment; C, carino-lateral compartment; E, carina. These letters are placed opposite the inward folds of each compartment. 2 _b_, " " minute portion of external surface of wall, magnified. 3 _a_, Tubicinella trachealis, natural size; _p_, tubular soft lip leading into sack; _s_, scutum; _t_, tergum. 3 _b_, Tubicinella trachealis, carino-lateral compartment of a young specimen, natural size; _e_, broken summit of wall; _d_, radius: the dotted lines, connecting the two figures, show the size and form which this compartment would have attained, if it could have grown without the summit constantly breaking away. 3 _c_, Tubicinella trachealis, scutum and tergum viewed from within, and connected by layers of thickened membrane; the scutum is to the left-hand. 4 _a_, Xenobalanus globicipitis, enlarged; _b_, skin of the porpoise, with the shell imbedded; at _c_ the lower end of the prosoma of the included animal's body is supposed to be seen through. 4 _b_, Xenobalanus globicipitis, shell greatly enlarged, seen from above, with the basal membrane at the bottom; the peduncle-formed body having been removed. A, rostrum, on the inner side of this and the adjoining compartments, the transversely ribbed sheath can be seen. B, lateral compartment. C, carino-lateral compartment. E, carina; these compartments are separated by the sutures _s s_, which run from the top of the shell to the bottom, along the ends of the six rays formed by the adjoining portions of the inwardly folded compartments. _a_, alæ, of rectangular shape. _d_, pseudo, or complimentary radii. 4 _c_, Xenobalanus globicipitis, small portion of external surface of wall of shell, showing the external lamina, _a a_, which consists only of narrow ledges (expanding and contracting) on each side of the longitudinal septa, _c_; _b_, the internal lamina.

PLATE 18.

_Genus_--CHTHAMALUS.

Fig. 1 _a_, Chthamalus stellatus, shell, _var. a_ (communis). 1 _b_, " " " " _e_ (depressus). 1 _c_, " " " " _c_ (communis). 1 _d_, " " " " _d_ (fragilis). 1 _e_, " " scutum and tergum, viewed inside, _var. c_, British. 1 _f_, " " scutum and tergum, viewed inside, _var. a_, Madeira. 1 _g_, " " scutum and tergum, viewed inside, _var. e_, Mediterranean. 1 _h_, " " scutum and tergum, viewed inside, _var. c_ and _e_, St. Jago, Cape de Verde Arch. 2, Chthamalus antennatus, shell. 3 _a_, Chthamalus dentatus, shell; 3 _b_, _var._ shell, attached to a ship's bottom; 3 _c_, tergum, viewed from within. 4 _a_, Chthamalus cirratus, scutum, viewed on inside; 4 _b_, tergum, viewed on inside. 5 _a_, Chthamalus Hembeli, shell, old specimen. 5 _b_, Chthamalus Hembeli, younger shell; C, carino-lateral compartment; _a′_, ala; _d_, radius; E, carina; _a′_, the two alæ. 5 _c_, Chthamalus Hembeli, scutum, external view of; 5 _d_, tergum, external view of; _e_, two of the crests, to which the tergal depressor muscles are attached, much enlarged and viewed from vertically beneath, showing the lateral denticuli or sub-crests. 6 _a_, Chthamalus fissus, shell; 6 _b_, scutum and tergum, separated, internal views of.

PLATE 19.

_Genera_--CHTHAMALUS, CHAMÆSIPHO, AND PACHYLASMA.