572 BULLETIN 54, UlsriTED STATES NATIONAL MUSEUM. 



head in a small lobe. Eyes absent. The first pair of antennfe are com- 

 posed of "'three" articles. The second pair are composed of '""five" 

 articles. Both pairs are small and inconspicuous in a dorsal view. 



The seven segments of the thorax are distinct. Ovarian bosses are 

 present on the sub-lateral anterior portion of the lateral margins of 

 the first four segments. The epimera of these segments are ver}- 

 narrow plates, lateral to the ovarian bosses. On the last three seg- 

 ments the epimera are narrow plates occup3'ing the anterior portion 

 of the lateral margin. 



All six segments of the abdomen are distinct. The lateral parts of 

 these segments are not produced. The lateral margins are straight. 

 The sixth or terminal segment is very small and posteriorly truncate. 

 There are no uropoda. The pleopoda are represented by fleshj" ridges. 



There are five pairs of incubatory lamella?. The distal portion of 

 the first pair has the posterior margin not produced in a lolie. 



The seven pairs of legs ai'e small, ^^•ith prehensile hands and the 

 basis furnished with a high, more or less rounded, carina. 



The male is elongate, 3 mm. long and 1 mm. wide. Head with the 

 anterior margin rounded. Eyes distinct. The first pair of antenna? 

 are composed of three articles. The second pair are composed of four 

 articles. All the thoracic segments are distinct, with straight lateral 

 margins. The legs are prehensile. All the segments of the abdomen 

 are coalesced in a single segment which tapers posteriorly to a point. 

 There are no uropoda or pleopoda. 



Family XXI, DAJID.E," 



" Body of female synnnetrical. Segmentation, when present, only 

 visible in the middle of the dorsal surface. 



Palp of maxillipeds wanting, 



Incu])atory plates small, often reduced in number. Incubatory 

 pouch (;ontined to the lateral parts of the bod\", one cavity on either 

 side, 



Onlv four or five pairs of legs present, crowded around the oral area. 



Pleopoda usuall}' rudimentary or entirely wanting. 



Uropoda developed or absent, 



Male with the first thorasic segment coalesced with the head. 



Parasitic on Schizopoda. 



ANALYTICAL KEY TO THE (JENERA OF THE FAMILY DA.TID.E. 



a. Body of female distinctly yegmented in the dorsal region. Uropoda present. 



First pair of })leopods well developed; following pairs rudimentary. 



Genus Dajnx Kr0yer 

 «/. Body of female without any trace of segmentation. Uropoda absent. Pleopoda 



wanting Genus Holophryxus Richardson 



«See G. O. Sars for characters of family, Crust, of Norway, II, 1899, p. 221. 



