no. 1136. OBSER VA TWNS ON THE ASTA CIDM— FAXON. 673 



Astacus bicarinatus Hess, Arch. f. Naturgesch., 31ter Jahrg., I, p. 164, 1865 (after 



Gray; no description). 

 Astacus bicarinatus von Martens, Monatsber. Akad. Wissensch. Berlin, 1868, 



p. 617. 

 ' Astacoides bicarinatus McCoy, Prod. Zool. Victoria, Decade III, pi. xxix, 1879. 

 Astacopsis bicarinatus Haswell, Cat. Australian Stalk- and Sessile-eyed Crust., 



p. 177, 1882 (after Gray). 

 Cheraps bicarinatus Ortmann, Zoolog. Jahrb., Abth. f. Syst., VI, p. 7, pi. i, fig. 2, 



1891; Seinon's Zoolog. Forsch. in Australien, V, 1 Lief., p. 21 (Denkschr. 

 1 med.-naturwissensch. Gesellscb. zu Jena, VIII), 1894. 



f Cheraps preissii Ortmann, Zoolog. Jahrb., Abth. f. Syst., VI, p. 8, pi. i, fig. 1, 



1891. 



Habitat. — Australia. Port Essington (Gray), Cape York (von Mar- 

 tens), Bockhampton (Ortmann), Manning River (Haswell), Sydney 

 (Coll. Mus. Coinp. Zool.), Murray River (von Martens), Melbourne (Coll. 

 Mus. Comp. Zool.). 



Gray's description and figure of Astacus bicarinatus (from Port Es- 

 sington, northern Australia) do not apply very closely to the species 

 now commonly known by this name. The wrist, for instance, is described 

 and figured as "triangular, angularly produced in front;" the areola is 

 too broad, and the account of the carinse on the tail fin is not at all clear. 

 Gray's type should be in the British Museum. In close connection with 

 his description of A. bicarinatus. Gray notices a drawing brought home 

 by Eyre, representing the " Ukodko," or smaller crayfish of the Murray 

 River — undoubtedly the Cheraps bicarinatus of more recent authors. 

 Gray's failure to identify the " Ukodko" with his own Astacus bicari- 

 natus may have been due to the inaccuracy of the drawing, which 

 showed no indications of the carina} or postorbital ridges. 



Cheraps bicarinatus attains to a length of about 6 inches. The ros- 

 trum is long triangular in outline, plane above, the margins slightly 

 raised, commonly armed with a minute tooth on each side near the tip ; 

 but the lateral teeth are wholly wanting in some individuals. The 

 postorbital ridges may terminate anteriorly in a blunt tubercle, or in 

 others they may be quite free from any tendency to develop tubercle 

 or spine. The areola is narrow, widening gradually from the anterior 

 end backward. The antennal scale is very broad, broadest at the 

 distal end, its inner margin very convex. In large specimens the 

 dactylus of the chelipeds is equal in length to the inner margin of the 

 palm, but in small specimens the fingers are commonly longer in pro- 

 portion to the palm. The upper surface of the hand is sparsely and 

 not very conspicuously punctate, the punctations being most evident 

 on the outer half of this surface. 



According to Mr. Eyre, as quoted by Gray, this crayfish (known to the 

 aborigines of the Murray River district as the UJcodlco or Koongola) 

 "is found in the alluvial flats of the river Murray, in South Australia, 

 which are subject to a periodical flooding by the river. It burrows deep 

 below the surface of the ground as the floods recede and are dried up, and 

 remains dormant until the next flooding recalls it to the surface. At 

 Proc. N. M. vol. xx 43 



