152 



THE VOYAGE OF H.M.S. CHALLENGER. 



FIG. 34. — Inner an- 

 tenna of right side, 

 seen from above. 

 From a drawing by 

 v. Willemoes Suhm. 



Fig. 35. — Outer antenna 

 of right side, with 

 scale, seen from below. 

 From a drawing by 

 v. Willemoes-Suhm. 



to a strong, sharp tooth, directed upwards obliquely and anteriorly, extending beyond 

 the extremity of the third joint of the peduncle, having the margin serrate with 

 several small teeth, mingled with long hairs ; the fissure leading to the auditory 

 chamber is armed on the outer extremity of the posterior margin with one strong, sharp 



tooth ; the second and third joints of the 

 peduncle are cylindrical, and the third is shorter 

 than the second ; the terminal flagella are un- 

 equal, the outer being much more slender than, 

 and about one-fourth the length of the inner. 



The second pair of antennae (c) is implanted 

 just outside the first, and the coxa carries a 

 large curved phymacerite (o.p.) the extremity 

 of which is rather smaller in diameter than 

 the rest of the shaft, and is bent up against 

 and lodged in a depression on the outer and 

 under surface of the first joint of the first pair 

 of antennas ; the second and third joints are 

 closely impacted into one, so that it is difficult 

 to determine which is the second and which the third ; the inner anterior angle is armed 

 with a strong sharp tooth, and the outer supports a long and pointed scaphocerite fringed 

 with hairs ; on the under surface, behind the scaphocerite, is a large fasciculus of soft 

 hairs ; the last two joints of the peduncle are subcylindrical, and each produced to a 

 strong, pointed cusp or tooth at the outer distal angle, the most distant of which 

 reaches beyond the extremity of the scaphocerite ; the flagellum is of about the same 

 length and size as the inner branch of the first pair. 



The mandibles and other oral appendages offer nothing to distinguish them from 

 those of the other species. 



The first pair of gnathopoda supports a small rigid process fringed with hairs, attached 

 to the outer distal angle of the coxa, the rudiment apparently of a mastigobranchial 

 appendage ; the basis is armed on the inner surface with a row of strong cusps or blunt 

 teeth ; the ischium is short ; the meros long and ovate ; the carpos is cylindrical, slightly 

 curved, broader at the distal extremity than at its rneral ; the propodos is short, 

 cylindrical, smaller in diameter than the carpos, and armed with a few spine-like hairs ; 

 the dactylos is slender, sharp, and styliform. The entire appendage is fringed with long 

 and strong hairs on the inner and distal surfaces, and with short, fur-like hair on the 

 outer. 



The second pair of gnathopoda carries a rudimentary membranous mastigobranchial 

 appendage attached to the outer extremity of the coxa: the basis is short, the ischium long; 

 the meros half the length of the ischium ; the carpos shorter than the meros ; the propodos 



