AUSTRALIAN MALACOSTRACA. 173 



forwards ; the lateral cornua a little smaller, smooth above and 

 below ; anterior margin of the carapace near the orbit with a 

 single spine. Spaces between the spines smooth. Carapace 

 with a deep transverse sulcus in front of the posterior margin. 

 Abdomen punctate ; covered with scattered miliary granules, 

 not sulcate in the middle, the lateral cornua armed behind with 

 several acute teeth. Length 15 in. 



New South "Wales. 



This is the common Sydney Crawfish. Mr. T. "W. Kirk has 

 described and figured in the Transactions of the New Zealand 

 Institute for 1S79, under the name of P. tumidus, a species of 

 rock-lobster obtained in the North Island, and mentions that 

 Dr. Hector had told him that it is the same species as the common 

 crawfish of the Sydney Market. The differences between P. 

 tumidus and P. Hiigelii he states to be, (1) the greater size of 

 the former, (2) the upward curvature of the beak, supra-orbital 

 and antenuary spines, (3) the telson in the former being less 

 triangular and rounded instead of scarped. Leaving size out of 

 consideration, the upward (and forward) direction of the spines 

 mentioned is, so far as can be seen, present in P. ffitgelii, as 

 described and figured by Heller ; and there is such a close 

 agreement in all other points between that species and the 

 Sydney crawfish, that I am inclined to regard the concave 

 posterior border of the telson shewn in the figure (but not men- 

 tioned in the description), to be either an artist's slip, or the 

 result of the wearing of the posterior thin edge of the 

 telson in the specimen figured. 



In young specimens of the Sydney crawfish the spines on the 

 carapace are very prominent, and all without exception pointed 

 as represented in she " Eeise der Novara," but in large speci- 

 mens many of them become blunt, and reduced to the appearance 

 of tubercles, as described by Mr. Kirk in the large New Zealand 

 specimen. 



Family ASTACIDM 



Carapace oblong, sub-cylindrical, rostrate, scarcely narrower 

 than the abdomen. External antennse provided with a basal 

 scale. First three pairs of ambulatory legs chelate. Sternum 

 narrow. 



