Zoologt/.'i NATURAL HISTORY OF VICTORIA. {_Crustacea. 



Plate 160. 



ASTACOPSIS SERRATUS (Shaw sp.), 

 VAR. YARRAENSIS (McCoy). 



The Yarra Spiny Cray-fish. 



[Genus ASTACOPSIS (Hnx.). (Sub-kingdom Articulata. Class Crustacea. Order 

 Decapoda. Section Macrura. Tribe Astacidea. Family Astacidae. Sub-family Farastacinse.) 



Gen. Char. — Epistome long, flat. Antennoe with base fixed by edge of carapace ; scale 

 small ; thoracic sterna narrow from the approximation of the large basal joints of the legs ; 

 twenty-OQe gills and one rudiment. Podobranchi« six, destitute of upper posterior lamellae 

 and without dilatation of stem, and on first jaw-foot an epipodite with rudimentary branchial fila- 

 ments ; no podobranchioe on last pair of thoracic legs ; six anterior arthrobranchise on arthrodial 

 membrane of second jaw-foot to penultimate leg ; five posterinr arthrobranchiaj on arthrodial 

 membrane from third jaw-foot to penultimate pair of legs ; four pleurobranchise on epimera of 

 four last thoracic joints. Australia.] 



Six months after I published in the Second Decade the illustra- 

 tion of the Murray Cray-fish (A. serrahis), and about a month 

 after I published in the Third Decade the account of the Yabber 

 Cray-fish (A. bicarinatus), there was published the number of the 

 Proceedings of the Zoological Society of London containing 

 Professor Huxley's remai'kable paper on the classification and 

 distribution of the Cray-fish, and I gladly recognise the internal 

 anatomical peculiarity of the Australian Cray-fishes which he has 

 pointed out, characterising his family ParastacidcB, peculiar to the 

 Southern Hemisphere, and differing from those of the other half of 

 the world in the podobranchiaj having no lamina, and in the first 

 joint of the abdomen being destitute of appendages in both sexes. 

 In these the anterior edge of the carapace overlaps and fixes the 

 basal joint of the antennge, and the posterior thoracic sterna are 

 very narrow ; the coxopodites of the posterior thoracic legs are 

 large and approximate in the midline, and the rostrum and anten- 

 nary scale short, and the telson, or last joint of the abdomen, is 

 never divided by a transverse joint ; the podobranchise of the first 

 jaw-foot or maxillipede is like an epipodite, but has some branchial 

 filaments not present in the Potamobiidce. The branchial filaments 

 of the podobranchia and the coxopoditic set£e have hooked tips 

 generally, not found in the northern family. 



{: 225 ] 



