166 BULLETIN 54, UNITED STATES NATIONAL MUSEUM. 



"Telson triang-ular, about two-thirds as long- as })road, lateral mar- 

 gins somewhat excavated, apex narrow, rounded. 



"Seventeen specimens from stations 6062 and 6063, 25 to To fathoms. 

 Largest 8.5 mm. by 3.8 mm. ; smallest 5.5 mm. by 2.5 mm." — Moore." 



Family VIII. ^GID^. 



Body more or less broad, flattened. 



Head transverse. 



Segments of thorax with epimera distinctly defined on all the seg- 

 ments, with the exception of the first. 



Al)domen composed of six well-defined segments, the last segment 

 ciliated on the posterior margin. Uropoda together with the terminal 

 abdominal segment forming a caudal fan. Eyes, when present, usually 

 large. Antenna^ laterally directed, both pairs furnished with distinctly 

 defined, multi-articulate flagella. Peduncle and flagella well defined. 



First three pairs of legs prehensile, last four pairs ambulatory. 



Pleopods serving for swimming and for respiration; furnished with 

 cilia. 



First maxillae with only a single slender masticatory lobe, tipped b}^ 

 short spines. 



Second maxillse broader, terminating in two unequal lobes, armed 

 with recurved teeth. 



Last article of palp of maxillipeds armed with strong recurved teeth. 



Terminal abdominal segment and uropoda furnished with cilia. 



Parasitic forms usually found attached to the skin of fishes. 



ANALYTICAL KEY TO THE GENERA OF THE FAMILY ^GID.E. 



a. Body compact. First two articles of the peduncle of the first pair of antennse 

 more or less expanded. Frontal lamina large. Maxillipeds with the palp com- 

 posed of five articles. Front of head with median point separating wholly or 

 partly the first articles of the first pair of antenn;e. Flagellnm of the first anten- 

 nae composed of numerous articles. Abdomen compact Genus ^Ega Leach 



a^. Body depressed. First two articles of the peduncle of the first pair of antennae 



not expanded. Frontal lamina small. Maxillipeds with the palp composed of 



only two articles. Front of head covering more or less the peduncle of the first 



pair of antenna\ Flagellnm of first antemue composed of four to six articles. 



Abdomen relaxed. 



b. Eyes present. Three anterior paii's of legs with propodus more or less expanded, 



and armed with spines; dactylus forming a very large and evenly curved 



hook. Four posterior pairs with the proi>odus short. Mandi])les with the 



cutting edge expanded inside in a linguiform lamella. Abdomen not much 



narrower than thorax Genus Roc'mela Leach 



I/. P]yes wanting. Three anterior pairs of legs with propodus not expanded; dactylus 

 abrui)tly curved in the middle and terminating in a very sharp point. Four 

 posterior pairs with the propodus elongated. Mandibles without linguiform 

 lamella. Al)domen abruptly narrower than thorax. .Genus Si/scenus Harger 



«Bull. U. S. Fish Commission, XX, Pt. 2, 1902, pp. 169-170. 



