100 THE VOYAGE OF H.M.S. CHALLENGER. 



and decidedly tortuous. The last two paii's of legs are folded up on the sides of the 

 carapace ; those of the third pair are one-half longer than the fourth pair and extend 

 forwards as far as the sides of the eye-stalks, the joints are smooth, and a few hairs are 

 present on the borders, the dactylus is small and curved, forming a perfect chela with 

 a similar process of the propodus, which latter bears two or three minute teeth on its 

 inner margin, and a hiatus exists between the two processes ; the legs of the last pair 

 are slightly more cylindrical, and are situated over the branchial regions, their margins 

 are somewhat pubescent, and the terminal chela is without a hiatus between the claws. 



The abdomen is short and stout ; the first pair of appendages are of small size in the 

 female, whereas in the male they are large and closely applied together in the middle line; 

 the second pair in the male are long and slender ; the lateral appendages in the female 

 consist of an elongated protopodite, a long slender and curved exopodite, and a shorter 

 and stouter endopodite. The penultimate segment is crossed by a transverse impression, 

 and its lateral appendage on each side bears a long and slender exopodite and a rudi- 

 mentary endopodite ; the ultimate segment is somewhat rectangular, and its free margins 

 are ciliated. 



The above description is taken from the larger (female) specimen, which gives the 

 following measurements: — Length of body 20 mm., of carapace 11 mm., of chelipede 

 25 mm., of third right leg 31 mm., of ocular peduncle 4 mm. The male specimen 

 measures only 18 mm. in length, and in it the left chelipede exceeds the right by more 

 than half the length of its fingers. 



Habitat. — Station 204a or B, off Tablas Island; depth, 100 to 115 fathoms; bottom, 

 green mud. Two specimens, male and female, both apparently adult. 



Genus Pylocheles, A. Milne-Edwards. 



Pylocheles, A. Milne-Edwards, Bull. Mus. Comp. Zoul., vol. viii. p. 38, 1880. 



Carapace completely calcified ; front with the rostral projection but slightly marked. 

 Ocular peduncles long and slender, the ophthalmic scales of small size and separated by 

 a considerable interval. Antennules of moderate length. Antennal acicle short and 

 stout ; the flagellum short. Chelipedes of equal size ; the fingers moving in an oblique or 

 almost horizontal plane, and corneous at the tips. Ambulatory limbs slender, with short 

 dactyli; the penultimate pair of legs subchelate. Abdomen symmetrical and well developed, 

 the segments with broad semi-calcareous terga, the ventral region membranous and provided 

 with rudimentary sterna on the first and sixth segments ; males with two pairs of genital 

 appendages on the ventral aspect of the first two segments, and a pair of symmetrical 

 biramous appendages on the third, fourth, and fifth segments ; females with a single 

 minute pair* of genital appendages on the ventral aspect of the first segment, and four pairs 

 of symmetrical l^iramous appendages on the second, third, fourth, and fifth segments, of 



