356 A HISTORY OF RECENT CRUSTACEA 



loped to be regarded as larval forms. It is very singular 

 that they are devoid of the last pair of peraeopods. Apart 

 from this extremely distinctive feature it might be sup- 

 posed that the species belonged to the genus Olencira, with 

 the somewhat variable type-species of which it agrees in 

 having a very small ' palp ' to the maxillipeds, the hinder 

 legs very elongate, with long curved nails, and the pleon 

 narrow, with a subtriangular termination. It differs in 

 having no eyes. 



C udonoyhihi s^, Haswell, 1881, is placed by its author 

 among the Cymothoidte, in Dana's subfamily ^gathoinee, 

 and the type-species, Codonoiiliilus arg^is, Haswell, is said 

 to approach JEgafJioa, Dana. The mandibles have the 

 ' palp ' elongate. The maxillipeds are small, operculiform, 

 three-jointed, the small basal joint probably not being 

 reckoned in. The uropods have a single ramus which is 

 falciform and carries a few scattered cilia. By the single 

 ramus of the uropods this genus would seem to approach 

 the family Sph«romida3. 



Family 4. — SeroUdce. 



The body is strongly depressed ; the broad head is 

 united, with or without a suture, to the first segment of 

 the still broader perseon. The seventh segment of the 

 peraeon is without side-plates, this and sometimes also the 

 sixth being dorsally fused with the pleon with or without 

 suture ; ventrally also these two segments are more or less 

 closely united. The side-plates of the sixth segment are 

 the longest. The pleon consists of three small free seg- 

 ments and a large terminal composite one. The pair of 

 eyes are rarely absent. The second pair of antennae are 

 not greatly longer than the first. The powerful mandibles 

 have a three-jointed ' palp ; ' the five-jointed maxillipeds 

 form an operculum over the two delicate pairs of maxillaB. 

 The first gnathopods are subchelate. The second are 

 similar to the first in the male, except that they are 

 smaller, but in the female they are similar to the following 

 pera;opods. The last perteopods are smaller than any 



