828 



CRUSTACEA. 



twice as long as the latter, and the joints of the flagella twice as 

 numerous, and the extremities of both the first and second pairs of 

 legs may be entirely unlike, so that when the second pairs are dis- 

 similar, we cannot look to the first as a guide to determine identity 

 of species. 



The relative lengths of the five posterior pairs of legs ; the number 

 and size of the hairs or setules on the legs, and their length, as com- 

 pared with the diameter of the joints ; the length and size, in the 

 same manner, of the hairs on the antennae ; the size of the epimerals ; 

 the length and relative size of the caudal stylets, — appear to be con- 

 stant characters for both sexes. The young, however, differ from 

 adults in these respects, as well as others, their antennae being not 

 only shorter but far less hairy, and the legs and stylets shorter, and 

 also more nude. 



Family I. DULICHIDJE. 



There is but one known genus of "this family — Dulichia of Kroyer.* 

 It has the legs of the fifth, sixth, and seventh pairs subequal and pre- 

 hensile, as in Caprella, and the first and second pair are furnished with 

 hands, the latter the larger. The four antennae are long, the supe- 



* Tids. [2], i. 512, 1845, and Voy. Scand., etc., pi. 22, fig. 1. He thus describes 

 the genus : — 



" Corpus valde elongatum, gracile. Antennae longissimae (imprimis superiores), sub- 

 pediformes ; superiores flagello instructs appendiculari. Oculi prominentissimi, acu- 

 minata Pedes thoracici lmi paris compressi, manu (articulo 4to) magna, ungueque 

 2-articulato instructi (qui unguis articulo 5to Gtoque junctis emcitur). Pedes 2di paris 

 manu instructi subchaeliformi (quae apud mares maxima est). Pedes 3tii 4tique paris 

 minimi, fere filiformes, invicem ejusdem ferme longitudine et forma. Pedes 5ti 6ti 

 7mique paris elongati, lineares (femore non dilatato), prehensiles. 6tus thoracis annulus 

 cum 7mo coalitus ut difficilius distinguantur. Epimera nulla vel prorsus rudimentaria. 

 Abdomen 5 modo compositum annulus et 5 praeditum pedum paribus quorum tria ante- 

 riora natatoria, duo posteriora saltatoria sunt." 



