174 ANELASMA SQUALICOLA. 



The final cause of the downward growth of the bottom 

 of the peduncle, is obviously to allow of the animal bury- 

 ing itself in the shark's body, in the same way as Coro- 

 nula and Tubicinella become imbedded by the downward 

 growth of their parietes in the skin of Cetacea. The 

 only other genus of Lepadidse, in which the growth of the 

 peduncle is at all analogous, is Lithotrya, in this genus, 

 however, the animal burrows mechanically into soft rock 

 or shells. 



I looked in vain for cement, or for the cement-glands, 

 (but the specimen was in an extremely unfavorable state 

 for finding the latter) or for the prehensile antennae of 

 the larva. No doubt this Cirripecle at first becomes 

 attached in the same way as others, but after early life, I 

 suspect it is retained in its place, by being so deeply im- 

 bedded in the shark's body, and perhaps by the root-like 

 branched filaments. The irregular growth and splitting 

 of the membrane at the base of the peduncle, where the 

 prehensile antennae of the larva must originally have been 

 situated, would account for not finding them. 



The inside of the peduncle (fig. 2 g) was gorged, in the 

 specimen examined by me, with immature ova. The in- 

 nermost muscular layer consists of longitudinal bundles of 

 unusual size, but placed rather far apart from each other ; 

 these do not extend to the very base of the peduncle, and 

 at the upper end they curve inwards, almost to the middle 

 of the under side of the diaphragm, separating the 

 peduncle and capitulum. Outside these longitudinal 

 muscles, there are delicate transverse ones, but apparently 

 there are no oblique muscles in the upper part of the pe- 

 duncle, as in other Lepadidae; near the bottom, the 

 transverse muscles form a thicker layer with many of the 

 bundles running in oblique lines. 



Mouth. — Loven has not described this part quite accu- 

 rately, owing to his not having used high enough magni- 

 fying powers. He states that the tropin are soft and 

 functionless, which is far from the case. The whole 

 mouth (fig. 2d), is unusually small ; it is, to a certain 



