58 STALK-EYED CRUSTACEA. 



between the eye-stalks, forming a blunt rudimentary rostrum. Tlie gastric 

 i-efion is sharply detineil, and presents an indistinct longitudinal furrow on 

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

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

 separated from one another by a re-entrant angle formed by the curving 

 forward of the posterior border of the carapace on each side of the median 

 line. 



The eye-stalks 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 antennular pedun- 

 cle is about two thirds the length of the eye-stalk, 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 flagel- 

 lum is about one half as long as the superior, and is composed of about 

 eleven segments. The peduncle of the antenna surpasses the eye-stalk by 

 one half the length of its distal segment; the acicle is long and slender, 

 tipped with a few setas ; 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 sette, 

 which assume a tomentose appearance on the chelce ; the carpus is about 

 equal in length to the chela, its inner face is perpendicular, the inner mar- 

 gin of the upper side is armed with seven small spines, and tliei-e is also 

 a spine at the distal end of the superior margin ; the chela is short and 

 thick, the fingers about the same length as the basal portion of the propodite, 

 slightly downcurved, meeting throughout their length, working horizon- 

 tally. The ambulatory legs are of nearly equal length, surpassing the cheli- 

 ped.s, setose, the carpus armed with a sharp tooth at the distal end of its 

 upper side ; the propodite is twice as long as the carpus, tlie dactylus is 

 considerably longer than the propodite, and like that segment is distinctly 

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

 abdomen; 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. 



