MUSEUM OF COMPARATIVE ZOLOGY. 171 



merus and carpus of the chelipeds and all the segments of the ambulatory le^'s 

 from the ischium to the dactylus inclusive are banded transversely with bright 

 red on a yellowish ground. 



Catapagurus diomedege, sp. nov. 



The carapace is smooth and naked, and divided into an anterior and pos- 

 terior section by the cervical groove. The anterior margin projects slightly 

 between the eyestalks, forming a blunt rudimentary rostrum. The gastric 

 region is sharply defined, and presents an indistinct longitudinal furrow on 

 each side of the median line; it is lightly conve.x in both directions. The 

 branchial regions of the right and left sides are strongly inflated and sharply 

 separated from each other by a re-entrant angle formed by the curving for- 

 ward of the posterior border of the carapace on each side of the median line. 



The eyestalks are rather long and slender, being about equal in length to 

 the anterior section of the carapace. The ophthalmic scales are very small and 

 minutely bifid at the tip. The third segment of the antennulary peduncle is 

 about two thirds the length of the eyestalk, and increases in diameter from the 

 base to the distal end ; the superior flagellum is rather longer than the distal 

 segment of the peduncle, and its enlarged ciliated basal portion forms rather 

 more than one third of its whole length. The inferior flagellum is about one 

 half as long as the superior, and is composed of about eleven segments. The 

 peduncle of the antenna surpasses the eyestalk by one half the length of its 

 distal segment ; the acicle is long and slender, tipped with a few setse ; it 

 reaches forward a little beyond the eye ; the flagellum reaches beyond the tips 

 of the ambulatory legs. The chelipeds are nearly alike in shape and size ; 

 their segments are clothed with long setae, which assume a tomentose appear- 

 ance on the chelae ; the carpus is about equal in length to the chela, its inner 

 face is perpendicular, the inner margin of the upper side is armed with seven 

 small spines ; there is also a spine at the distal end of the superior margin of 

 the carpus ; the chela is short and thick, the fingers about the same length as 

 the basal portion of the propodus, slightly down-curved, meeting throughout 

 their length, working horizontally. The ambulatory legs are of nearly equal 

 length, surpassing the chelipeds, setose, the carpus armed with a sharp tooth at 

 the distal end of its upper side ; the propodus is twice as long as the carpus, 

 the dactylus is considerably longer than the propodus, and, like that segment, 

 is distinctly curved ; it is tipped by a small horny nail. The fourth pair of 

 legs is but slightly subcheliform ; the rasp is formed of a single row of scales. 

 There are three small rudimentary appendages on the left side of the ab<lo- 

 men ; the first and second of these are two-branched, the secondary branch 

 being exceedingly minute. 



The sexual tube, which issues from the coxal segment of the last thoracic 

 appendage of the right side, is very long in this species. 



Length of carapace, 5.5 mm. ; abdomen, 8 mm. ; cheliped, 12.5 mm. ; last 

 ambulatory leg, 17.5 mm. ; ocular peduncle, 2.5 mm. 



