A Monograph on the Sub-class Cirripedia Part 40

(_d._) Rostrum,

(_e._) Sub-rostrum, both viewed a little obliquely.

4. _Pollicipes spinosus_, one and a half nat. size.

5. _Pollicipes sertus_, one and a half nat. size.

TAB. VIII.

Fig.

1. A piece of rock bored in two directions by _Lithotrya dorsalis_, with the calcareous basal discs in the upper cavity, serving as a bridge for crossing an old cavity.

About twice natural size.

1_a'._ _Lithotrya dorsalis_, (nearly twice nat. size), with the basal calcareous cup adherent; (_a_), rostrum on same scale, seen externally.

1_b'._ _Lithotrya dorsalis_, rostrum and the rostral corners of the two scuta, together with a small portion of the subjacent membrane of the peduncle, with its calcareous scales; viewed externally, greatly magnified, showing the inferior crenated edges of the scales.

1_c'._ _Lithotrya dorsalis_, basal calcareous cup, one and a half the natural size; this is the largest specimen which I have seen.

2. _Lithotrya Nicobarica_, (magnified nearly twice;) attached to the rock, copied from Reinhardt; (_a_), rostrum on the same scale, with the other valves, seen externally; (_b_), section of the row of discs; (_c_), extreme point of the peduncle, extending beneath the row of discs.

2_a'._ Rock bored by _Lithotrya Nicobarica_, showing the row of calcareous discs, copied from Reinhardt.

3. _Lithotrya cauta_, magnified between seven and eight times; (_a_), scutum; (_b_), tergum.

3_c._ _Lithotrya cauta_, latus, greatly magnified.

3_d._ _Lithotrya cauta_, uppermost scales of the peduncle, greatly magnified.

3_e._ _Lithotrya cauta_, star-shaped discs of hard chitine, supported on a peduncle of the same substance, taken from the lower exterior surface of the peduncle, very greatly magnified.

4. _Lithotrya Rhodiopus_, (magnified five times,) internal views of; (_a_), scutum; (_b_), tergum; (_c_), latus; (_d_), carina.

5. _Lithotrya Valentiana_, (magnified between three and four times;) (_a_), internal view of scutum and tergum, locked together; (_b_), capitulum seen from vertically above; (_c_), internal view of carina; (_d_), section across the middle of the carina.

TAB. IX.

Fig.

1. _Lithotrya truncata_, (magnified four times.)

1_a'._ _Lithotrya truncata_, capitulum seen from vertically above, not so distinctly represented as in fig. 5 _b_, Pl. VIII.

1_b'._ _Lithotrya truncata_, internal views of valves; (_a_), rostrum, with a few subjacent scales of the peduncle; (_b_), scutum; (_c_), tergum; (_d_), carina.

2. A portion (about 1/10th of an inch square) of the surface of attachment of the peduncle of _Pollicipes polymerus_, seen from the outside, greatly magnified, showing the small circular (_bb_) patches of cement, poured out from the cement-ducts (_aa_) which lie within the peduncle.

2_a'._ A portion of a section, still more magnified, through the basal membrane of the peduncle, through one of the loops of the cement-ducts (_aa_), and through one of the circular patches (_b_) of cement.

3. Cement gland, duct, and ovarian tubes of _Conchoderma aurita_; (_aa_), ovarian tubes, with ova in process of formation; (_b_), cement-gland; (_c_), cement-duct.

4. _Conchoderma virgata_, enlarged, with one side of the capitulum and of the peduncle removed, to show the form and position of the body.

(_a._) tergum, edge of.

(_b._) mouth, with one of the palpi seen on the inner, upper corner.

(_c._) adductor scutorum muscle.

(_d._) orifice of acoustic (?) sack.

(_e._) scutum, occludent margin of.

(_f._) branching ovarian tubes within the peduncle.

(_g._) filamentary appendage on the prosoma.

(_h._) ditto, close to basal articulation of the first cirrus.

(_i._) ditto, on the pedicel of the first cirrus.

(_j._) ditto, on the pedicel of the third cirrus.

(_k._) ditto, on the pedicel of the fourth cirrus.

(_l._) ditto, on the pedicel of the fifth cirrus.

(_m._) edge of the carina.

(_n._) prosoma.

5. Apex of one of the filamentary appendages of _Conchoderma aurita_, greatly magnified, exhibiting the included branching testes.

6. Acoustic (?) sack of _Conchoderma virgata_, taken out of the acoustic meatus, with the diaphragm from the summit removed; greatly magnified.

7. Terminal part (magnified seven times), of the peduncle of an elongated specimen of _Scalpellum vulgare_, slit open, with the corium removed, showing the two cement-ducts (_aa_), and a row of circular patches (_bb_) of cement, by which the peduncle, along its rostral edge, is attached to the thin h.o.r.n.y branches of the coralline. The larval antennae are seen at the terminal point, and the two cement-ducts can be traced into them.

TAB. X.

_Figures all greatly magnified._

Fig.

1. Mandibles of _Pollicipes mitella_: exhibiting the upper (_a_) and lower (_b_) articulations, and the three princ.i.p.al muscles; the short upper cut off muscle runs to its attachment at the base of the palpus.