ZOOLOGY 



presence of a carapace — which leaves some of the posterior 

 thoracic segments free — and in the number both of segments 

 and appendages, but present several interesting characters 



Fig. 49$. — Faranaspides lacnstris, x4. ai, antennules ; a2, antcnni»; Ab.l, first 

 abdominal segment : ep, epipodites or gills on the thoracic legs ; md, mandihle ; Ff.l, first 

 abdominal appendage ; 2', telsun ; Th,y, eighth free thoracic segment ; [f, uropod. (After 

 GcofErey Smith.) 



indicating a lower grade of organisation. One of the most 

 notable of these is the absence of differentiation in the thoracic 

 appendages, which, though they have a leg-like and not a leaf-like 

 form, are all alike, none of them being modified into maxillipedes. 



Fig. 409.— Mysis oculata. end. endopodito; e.f. cxopodite ; ot. otocyst. (After Ger.^taccker.) 



except to a very slight degree in some forms. Moreover, the legs 

 all possess exopodites (e,e), thus retaining the primitive biramous or 

 " split-footed " form which is lost in the Decapoda. The first five 

 pleopods are large in the male, small in the female: the sixth 



