300 POLLICIPES CORNUCOPIA. 



tuberant. Of the other valves, including the sub-carina 

 and sub-rostrum, the shape of their inner surfaces is sub- 

 triangular, with the basal margin convex ; externally the 

 umbones are pointed, and slightly curled inwards, so as 

 to overlap each other like tiles : the smaller valves, how- 

 ever, of the lower whorls (fig. 1 a) are more or less trans- 

 versely elongated, so as to become almost elliptic instead 

 of triangular. Of the latera, the upper pair, which cor- 

 responds to the interspace between the scuta and terga, is 

 the largest, but barely exceeds in size the pair answering 

 to the carina! latera in Scalpellum, which lie between 

 the terga and carina : the next largest pair is the rostral, 

 or that between the scuta and rostrum. Some, however, 

 of the lower latera are of nearly equal size. 



Peduncle, narrower, but generally longer than the 

 capitulum ; upper part encased with small calcareous scales, 

 with their apices curved inwards, and overlapping each 

 other. The inner surface of each scale is triangular, with 

 the basal margin protuberant. The scales continue to 

 grow or be added to, only in about the ten upper whorls, 

 which form but a small part of the whole peduncle ; in 

 the lower part, the scales become further and further 

 separated from each other. The surface of attachment, 

 in full-grown specimens, is broad ; but in two very young 

 specimens, which I removed with great care after the 

 action of potash, I found the peduncle ending in a filiform 

 prolongation, such as often occurs in Scalpelhwi vulgar e 

 and in Lepas fascicularis. At the extremity of the pointed 

 peduncle, there were seated the larval prehensile antenna^ 

 of which the following measurements are given to show 

 how minute they are. 



Inch. 

 Length, from apex of disc, to the further edge of the basal articulation boos 

 Breadth of basal segment, in broadest part .... ^ m 

 Hooi'-like disc, length of ....... so %> 



Ultimate segment, entire length of m ^ 



breadth, in broadest part .... 5 oik> 



j> » 



The disc resembles a broad, rounded hoof, very little 

 longer than broad, and narrowed in at the heel; the 



