FRESHWATER CRAYFISHES OF AUSTRALIA. 1G3 



name GhcBraps for it, and placing the Western-Australian species 

 in a new genus, ParachcHraps. But, as ]\I. Koux, of the Basle 

 Museum, pointed out to me, the term Cltmraps was first used by 

 Erichson (Arch. f. Naturg. xii. 1846, p. 101) for the species 

 C. preissii, which, whatever it may be, does not seem to be 

 identical with P. hicarinatas. From Erichson's diagnosis of the 

 genus Clueyraps and of the single species C preissii, which he 

 includes in it, I find it quite impossible to discover what spaciea 

 of Australian Crayfish he was dealing with. No figures are given, 

 and the only characters mentioned whicli are of the slightest 

 diagnostic value are the facts that the animal came from Western 

 Australia, that the tail-fan was in part membranaceous, and that 

 the antenna! scale was " egg-shaped and pointed." No mention 

 w^hatever is made of any keels on the carapace, a point noticed by 

 Haswell in his ' Catalogue of the Stalk- and Sessile-eyed Crustacea 

 of the Australian IMuseum,' who gives as a chai-acter of C. preissii 

 " the absence of keels on carapace (?)." 



The balance of evidence seems favourable to the idea that 

 Erichson's really worthless description of Q. preissii does refer to 

 a species of Chcerajys and not to Parach(p/raps bicariiiatiis, so 

 that the term Chceraps must be kept for the Western- Australian 

 species. 



PARACHiERAPS BICARIXATUS GvdJ. (Pls. XXI. k XXVJ , 



figs. 15-24.) 



The Yabher. 



(Eyre's Journals of Expeditions of Discovery into Central 

 Australia, vol. i. 1845.) 



Nomenclature : — 



Astacus hicarinatus Gz'ay, loc. cit. p. 410, pi. iii. fig. 2. 



Ghiaraps hicarinatas Von Martens, Monatsbericht Akad, 

 Wiss. Berlin, 1868, p. 617. 



Astacopsis hicarinatus Haswell, Australian Museum Cata- 

 logues, v. CiiTStacea. 



Astacoides hicarinatas McCoy, Prodromns of the Zoology of 

 Victoria, vol. i. pi. 29, 1885. . 



The rostrum is without pronounced keels ; it terminates in a 

 spine, just belov/ wduch two small lateral spines indi&xte the 

 beginning of the much-reduced keel. 



The lateral carina on the carapace is a continuous blunt ridge. 

 There are no other tubercles or spines on the carapace or body 

 and there are no hairs except at the lateral borders of the 

 carapace and abdominal segments and on the liudis. ' The surface 

 of the carapace is, however, usually pitted superficially. 



The telson is bi-oadly ovate, and there are two small spines 

 laterally at the junction of the hard and membranous portions. 

 There are no median spines. 



In the great chela the dactylopodite is not larger than tho 



11* 



