MARINE GAMMARIDEAN AMPHIPODA 283 



dibular molar, a large palp on the first maxilla and an incised, broad- 

 ened upper lip. 



Superficially, the Lafystiidae resemble several other families through 

 the Laphystiopsidae [which should be consulted]. As discussed therein 

 the Laphystiopsidae are still considered distinct from Lafystiidae, 

 necessitating the removal of Prolaphystiopsis to the Laphystiopsidae. 



Genera of Laphystiidae 



Lafystius Kr0yer 



Lafystius Kr0yer, 1842.— Stebbing, 1906. 

 Darwinia Bate, 1857a. 

 ? Dernwphilus Beneden and Bessels, 1870. 

 fichthyomyzocus Hesse, 1873. 



Type-species: L. sturionis Kr0yer, 1842 (monotypy). See Sars, 

 1895. 

 Species: 1, boreal N.E. Atlantic, littoral, occurring on fishes. 



Laphystiopsidae 



FiGUKE 111 



Diagnosis. — Accessory flagellum absent; mandibular molar non- 

 triturative; gnathopods feeble, simple; telson entire. See Isaeidae, 

 Stilipedidae, Oedicerotidae, Calliopiidae, Pleustidae, Lafystiidae. 



Description. — Accessory flagellum absent; body broad, carinate 

 only on a few pleonites; urosomite 1 elongate or not; rostrum large 

 and spatulate or absent; upper lip incised; mandible bearing molar 

 process, simple or slightly triturative; lower lip with or ^\^thout inner 

 lobes; palp of maxilla 1 large, 1- or 2-articulate; maxilliped with 

 small 4-articulate palp; coxae variable, either very short and rectan- 

 gular and serially disjunct or of medium length, quadrate or slightly 

 acuminate and overlapping; gnathopods feeble, simple; outer rami of 

 uropods 1-2 slightly shortened; uropod 3 biramous, peduncle short; 

 telson short or of medium length, oval, entire. 



Relationship. — The Laphystiopsidae are simply Calliopiidae- and 

 Pleustidae-like organisms with feeble, simple gnathopods, feeble, 

 poorly setose maxillipedal palps and poorly developed mandibular 

 molars. Even the lower lip of the type-genus is similar to that of 

 Pleustidae, although Prolaphystius lacks inner lobes. Even Cleippides 

 and Regalia in the Calliopiidae have simple gnathopods. 



The Lafystiidae faintly resemble Laphystiopsidae but the latter 

 have lost the mandibular molar and spine row, two articles of the 



285-135 O - 69 - 19 



