MARINE GAMMARIDEAISr AMPHIPODA 147 



Aoridae 



Figures 63, 64 



Diagnosis. — Accessory flagellum variable, multiarticulate, or ab- 

 sent; telson entire, short, fleshy; coxa 4 not excavate posteriorly; 

 pereopods glandular; uropod 3 rarely projecting beyond uropods 1 and 2, 

 at least one of rami as long as or longer than peduncle; gnathopod 1 

 larger than gnathopod 2, in rare cases only as large as gnathopod 2 

 but with male secondary sexual modifications. See Isaeidae, Coro- 

 phiidae, Ischyroceridae. 



Description. — Accessory flagellum varying from absent to long 

 and multiarticulate; body smooth; rostrum vestigial; coxae rounded 

 or quadrate below, varying from long to short, fourth not excavate 

 posteriorly; mouthparts basic; gnathopods powerful, subchelate or 

 complexly subchelate, occasionally nearly simple, but then often 

 extremely setose, first always larger or more complex than second in 

 both sexes and bearing most of male secondary sexual modifications; 

 pereopod 5 usually conspicuously elongate; uropod 3 short, rami 

 usually as long as or longer than peduncle, occasionally inner ramus 

 reduced in size or both rami reduced; telson short, nearly circular or 

 square, entire, occasionally falsely (?secondarily) cleft. 



Relationship. — Like the Isaeidae but having an enlarged first 

 gnathopod; otherwise Aoridae are related to other families in the 

 same way as are the Isaeidae. Keys of both families and the Coro- 

 phiidae should be checked when examining any genera with abnormally 

 enlarged or complexly subchelate gnathopods. One may understand 

 the difficulties of segregating Aoridae and Corophiidae when examining 

 the small differences between Grandidierella (Corophiidae) and 

 Neomicrodeutopus (Aoridae) . 



Nomenclatural Changes in Aoridae 



The female of Dryopoides was first assigned to the Aoridae by 

 Stebbing (1888). Its first gnathopod is larger than the second. In 1910, 

 Stebbing discovered the male, with gnathopod 2 larger than 1, but the 

 species was transferred to the Corophiidae. Because the genus may yet 

 prove to be an aorid, the female is retained in the key to Aoridae as 

 if it were a male. 



Paradryope and Dryopoides might be placed in the family Ischyro- 

 ceridae, especially Paradryope because of the short rami of its uropod 

 3 and the slightly elongate peduncle. The uropodal peduncle of 

 Dryopoides is not greatly elongate. Ischyroceridae would thus receive 

 genera with gnathopod 1 larger than 2, of which Bonnierella is an 



