1894.] NATURAL SCIENCES OF PHILADELPHIA. 399 



the surface of the body and legs bearing a peculiar sculpture. The 

 most extreme species, Atya crassa, may be separated from the others 

 according to the sculpture of the body and placed in a separate sub- 

 genus, Evatya. 



Fossil Atyidce are not known, although A. Milne-Edwards 2 de- 

 scribes a Caridina nitida from the "marnes d'Aix- en-Provence" 

 (upper eocene or lower oligocene). None of the arguments given 

 by him prove that this fossil is a Caridina. The presence in a fresh- 

 water deposit makes it probable that it belongs to Atyidce, but for 

 the same reason Homelys minor of Meyer, 3 from the fresh-water de- 

 posits of the upper miocene of QEningen, would belong to the same 

 family. 



ATYIDJE Kingsley, 1879. 



Kingsley, Proceed. Acad. Nat. Sei., Philadelphia, 1879, p. 414. Bate, Challenger 

 Macrur., 1888, p. 691. Ortmann, Zoolog. Jahrh., V, 1890, p. 455. 



Mandibles stout, crown broad, dilated, slightly divided, without a 

 synaphipod. First four pairs of pereiopoda with epipodites. First 

 two pairs of pereiopoda chelate, nearly equal, carpus of the second 

 not annulated. Tips of fingers with pencils of hairs. Rostrum 

 longer or shorter, serrated or not serrated. 



a x . Pereiopoda with exopodites [Xiphocarince] . 



b x . All the pereiopoda with, exopodites. Carpal joints of the first 

 two pairs of pereiopoda not excavated or but indis- 

 tinctly so. 



c x . Eyes well developed . Xiphocaris. 



c 2 . Eyes rudimentary Troglocaris. 



6 2 . Only the first two pairs of pereiopoda with exopodites. Car- 

 pal joints of the first and second pair of pereiopoda distally 



excavated Atyaephyra. 



a 2 . Pereiopoda without exopodites \_Atyino3~\. 



b v Carpal joint of the second pereiopoda normal, not excavated. 

 Rostrum mostly compressed and serrated . . . Caridina. 

 6 2 . Carpal joint of the second pereiopoda like that of the first 

 distally excavated. 

 c 1# Movable finger shorter than the immovable part of 

 hand, the latter distinctly divided in a palmar por- 

 tion and an immovable finger Atyoida. 



c 2 Both fingers alike in size, no palma developed . Atya. 



2 Bull. Soc. Philomat., Paris (7), II, 1879, p. 77. 



3 Palseontographica, X, 3, 1862, p. 172, pi. 19, figs. 3-8. 



