462 



THE VOYAGE OF H.M.S. CHALLENGER. 



Fig. 67.- 



-Second siagnopod or 

 maxilla. 



Fig. 68.- 



Third siagnopod or 

 first niaxilliped. 



The second pair of siagnopoda is four-lobed, each lobe distally decreasing in size, and 

 furnished on the inner margin with a series of simple spinedike hairs, three ciliated spine- 

 like hairs and one small and simple ; the basal lobe is broader than the middle one but 



narrower than the distal, and is furnished with 

 four straight, spine-like, ciliated hairs; at the 

 posterior margin, corresponding in position 

 with the middle lobe, is a short but broad 

 ecphysis connected near the middle by a 

 short pedicle, and furnished at either extremity 

 with a series of simple hairs, that become 

 ciliated in the adult stage. 



The third pair of siagnopoda, or first 

 maxillipeds, is Inarticulate, the distal joint 

 being fringed on the inner surface with two rows of simple hairs, and the basal with a 

 few solitary hairs of the same character ; this organ approximates to that of the adult, but 

 it is more slender. 



The first pair of gnathopoda is six-jointed, the several joints being subequal, the 

 terminal one being broader and reflexed upon the preceding ; the 

 inner margin of each joint is fringed with simple hairs, the basal joints 

 sparsely, the distal copiously. 



The second pair of gnathopoda is longer than the first, it has no 

 ecphysis and consists of six joints fringed with a series of hairs. 



The pereiopoda are reduced to three pairs, the fourth not being 

 reproduced in this stage ; none of those present is furnished with an 

 ecphysis, and in general aspect, though not perfectly in detail, they 

 assume the appearance of those of the adult stage. The first pair 

 consists of four joints, of which the basisal is the longest. The second 

 pair is much longer than the second gnathopod, and consists of four 

 joints. The third pair is about the same length as the second, and 

 consists of five joints, of which the terminal is short and rudimentary, 

 and probably becomes in the adult the minute rudimentary dactylos 

 of the microscopic chela. 



Each somite of the pleon is armed with a prominent tooth projecting from the lateral 



Fig. 69.- First gnath- 

 opod. 



The pleopoda are all single-branched and Inarticulate, the four posterior support- 

 ing at the distal extremity of the basal joint a small bud-like process, that ultimately 

 develops into the future secondary ramus. The posterior pair of pleopoda together with 

 the telson is developed into a well-formed rhipidura, that bears a close resemblance to 

 that of the adult, the only immature feature being the greater proportion which the 



