i86 



THE CRUSTACEA 



endites present a close approximation to those of Tanaidacea and 

 Isopoda. In Campylaspis the endites are suppressed. 



The first thoracic appendages 

 with their respiratory epipodites 

 (Fig. 115) have a close resem- 

 blance to those of the Tanaidacea, 

 in which group, however, there 

 is no exopodite. The basipodite 

 has an endite directed distally, 

 and carries on its inner edge 

 two or three hooked spines 

 Fig. 114. (" coupling-hooks ") which inter- 



A, maxillula, B, maxilla, of Dlastylis Goodsiri. lock with thoSC of the Other side. 



1-4, segments of the appendaires ; il-Z4 endites rni i i ^i • i j.i 



of the respective segments ; /, flabellum (ex- 1 he SCCOUd and third thoraClC 



opodite) ; p, palp. According to Hansen's later 1i,-nV>«; tbnno-b Ipcjq qnppiib'qpd 



iuterpretation,thechitinous piece here numbered ^"""^j tUOUgU lebS bpecuiliseu, 



4 in the maxilla does not represent a distinct mav alsO be rcckoucd aS maxilH- 

 segment, and the endites 1 3 and I * result from r . . , . 



the division of a sins;le endite belonging to the pCCiS, SlllCC they are tumecl lOr- 



third segment. (After Hansen.) ^^^^^^^^ ^^^^ ^ppj-^^ ^^ ^j^^ ^^.^^j 



region with their basipodites ilattened and meeting in the middle 

 line, while the terminal segments are relatively 

 weak and carried in a folded position. The 

 second pair are without exopodites, but in the 

 female a small scale bearing a fan-like fringe 

 of setae is attached behind to the base of the 

 limb, projecting backwards into the marsupial 

 chamber and serving to keep in motion the 

 eggs or embryos contained therein. This scale 

 is doubtless homologous with the oostegites, 

 which are well developed on the four succeed- 

 ing pairs of limbs, where they are firml}^ 

 attached to the small coxal segments. The 

 third pair are only rarely devoid of exopodites. 

 The fourth pair of thoracic limbs are long 

 raptorial or prehensile legs (Fig. Ill, l^), 

 though their broad basipodites, sometimes 

 meeting in the middle line, are not dissimilar 

 to those of the preceding pair. The fifth pair 

 (2nd legs) often have a reduced number of 

 joints and differ in details from the succeed- 

 ing three pairs, which are all similar and appear 

 to be fossorial in function. The small terminal 

 segment in these limbs is tipped with a com- 

 paratively weak spine, which only in the 

 Nannastacidae becomes a stout curved claw. 



are always present on the fourth pair (1st legs), and usually on 

 one or more of the succeeding pairs in the female sex; in the 



Fig. 115. 



First maxilliped of Dia- 

 stylis atygvi. hs, basipodite ; 

 6/', branchial lamellae on 

 epipodite ; en, endopodite ; 

 ep, epipodite ; ex, exopodite, 

 forming the respiratory 

 siphon. (After Sars.) 



Natatory exopodites 



i-.-^^' 



