184 U.S. NATIONAL MUSEUM BULLETIN 271 



Genera of Colomastigidae 



Coloinastix Grube 



Colomastix Grube, 1861; 1864a.— Stebbing, 1906. 

 Cratippus Bate, 1862. 

 Exunguia Norman, 1869b. 



Type-species: Colomastix pusilla Grube, 1861 (monotypy). See 

 J. L. Barnard, 1955a. 



Species: 9, cosmopolitan, littoral. 



Corophiidae 



Figures 76-80 



Diagnosis. — Accessory flagellum variable, often absent; urosome 

 visibly depressed; urosomal segment 2 suhequal to segment 1 in length; 

 telson entire; pereopods often glandular. See Isaeidae, Aoridae, 

 Podoceridae, Ischyroceridae, Cheluridae. 



Description. — Accessory flagellum multiarticulate, 1-articulate or 

 absent; body often subcylindrical, generally depressed, especially 

 urosome, some or all of urosomites often coalesced; body rarely 

 carinate and only on urosome; coxae long, of medium length, or short, 

 often not touching each other, occasionally acuminate; mouthparts 

 basic, except mandibular palp occasionally reduced to one or two 

 articles and upper lip occasionally bilobed; gnathopods variable, 

 either pair the larger, often complexly subchelate; uropods 1 and 2 

 usually normal, rarely with inner rami reduced, rarely with inner 

 ramus on uropod 2 absent; uropod 3 variable: (1) bearing two rami, 

 the inner reduced in size; (2) bearing one ramus, either longer than 

 peduncle or very short ; or (3) rami absent ; telson entire, fleshy, circular 

 or symmetrically trapezoidal, or very broad and short, occasionally 

 armed with hooks; pereopod 5 occasionally very elongate and bearing 

 long setae like fossorial families. 



Relationship. — The Corophiidae are a mixture of isaeid, aorid, 

 and ischyrocerid kinds having the urosome especially depressed and 

 usually losing the inner ramus of the third uropods, although this 

 condition is found also in some isaeids. It is very difficult to distinguish 

 these three families, as exemplified by the genus Aorcho, originally 

 assigned to Corophiidae but now provisionally assigned to Aoridae 

 (see discussion under the Isaeidae). Because of its tall urosome, 

 Unciolella is another genus of doubtful assignment to the Corophiidae. 

 Neomicrodeutopus (Aoridae) and Grandidierella (Corophiidae) are very 

 closely related. 



