POLLICIPES POLYMERUS. 313 



midst of which a tuft of fine spines, as in the posterior 

 cirri, may be distinguished; the dorsal tufts encircle the 

 whole of each segment ; the spine-bearing anterior surfaces 

 are protuberant chiefly in the upper part, so that they are 

 oblique. The posterior (?) ramus has its segments much 

 wider than those on the other ramus ; and amongst the 

 common spines, in the third and fourth segments, (counting 

 from the bottom,) there are some very strong spines 

 with their upper ends coarsely and doubly pectinated, 

 each tooth being upwardly bent into a rectangular elbow. 

 In the fifth segment, some of the spines are doubly 

 pectinated with simple teeth ; and most of the spines are 

 doubly serrated. The Second (PL X, fig, 25) and Third 

 cirri have the five basal segments (-rVths of the whole 

 number in the second cirrus, and Tiths in the third cirrus) 

 of their anterior rami, extremely broad, protuberant, and 

 paved with serrated bristles, amongst which, (except on 

 the actual lowest segment,) there are some simply pecti- 

 nated spines, and others with their teeth elbowed, exactly 

 as in the first cirrus. The basal segments of the posterior 

 rami of the second and third cirri, differ from the three 

 posterior cirri only in the spines being slightly more 

 numerous ; but none of them are pectinated. 



Pedicels, rather short ; the upper segment resembles, in 

 the arrangement of its spines, the segments of the pos- 

 terior cirri ; the lower segment is longer than the upper, 

 and has two tufts of fine spines, between the two rows 

 of long spines. In the second and third cirri, these two 

 intermediate tufts on the lower segment of the pedicel, 

 are not so distinctly separated from each other. 



Caudal Appendages, very small, uniarticulate, blunt 

 and rounded ; tips bearing a few, very short, thick spines. 



Alimentary Canal. — (Esophagus, somewhat curved at 

 the lower end, where it enters the stomach, which has no 

 caeca ; rectum, unusually short, extending from the anus 

 only to the base of the fifth pair of cirri. Within the 

 stomach, from top to bottom, there were thousands of 

 a bivalve entomostracous crustacean. 



