Crustacea. 257 



The genns Nymphon is a large one, and a list of twenty -five reliable 

 and eleven doubtful species is given by Dr. Hoek (13) in the 

 ' Challenger'' Eeport referring to this class. 



Prof. 8ars, in 1891 (28), while adding a few species, divides the 

 genus into three — Niimplion, Choitowjmplion, and BoreoiiiimfJwn. 



IsTymphon austeale. 



(PI. XL..) 



Body robust, with lateral processes of a large size ; these are 

 setose, though the body is apparently smooth. Neck short and 

 constricted. Head segment two and a half times as long as the 

 following one. Ocular peduncle long, but very variable, sometimes 

 rounded at the extremity, sometimes obtusely pointed, and occa- 

 sionally much reduced in size. Lenses apparently rudimentary ; 

 sometimes four may be detected, but more commonly only two ; a 

 very large proportion of the specimens, however, only show an 

 irregular mass of pigment, the quantity and its precise position 

 being very variable. Proboscis cylindrical, directed downwards. 



Mandibles. Scape ^onger than proboscis, becoming stouter at its 

 distal extremity, and provided with stout setae, many of which are 

 very long. 



Chela stout, setose, the claws being longer than the propos 

 bearing them. They are slender, somewhat abruptly curved at the 

 tips, and beset along their entire biting edge with teeth, which, 

 though conspicuously large and small, are not arranged in strict 

 alternation. 



Palp slender, five-jointed ; the second joint is the longest, the 

 fifth is a little shorter than the preceding. All are setose ; the setae on 

 the two terminal joints being the smallest and the most numerous. 



Ovigerous legs, ten-jointed ; the first two are very small, and the 

 third is equal in length to the two, the fourth and fifth are much 

 longer, and sub- equal ; the last three are also sub-equal in length, 

 the terminal joint bearing a long pectinate claw. The last four 

 segments bear a single row of denticulate spines. 



These spines bear three or four lateral teeth on each side. The 

 entire limb is more or less setose. In the ovigerous individuals the 

 first six joints of this appendage are usually much swollen, and this 

 more particularly applies to the fifth joint. 



The four walking legs are alike. The second coxa is conspicuously 

 the larger of the tliree, and the third l^ears a prominent swelling on 



