178 



HIALMAR RENDAHL 



Through the courtesy of the Trustees of the Austrah'an Museum 

 in Sidney, I received a series of specimens from Eastern Au- 

 stralia, viz , 30 specimens determined as M. nigrans from Ryle- 

 ston, Cudgegong R., N. S. Wales, 18 specimens of the same 

 form from Colombo Creek, near Narrandera, N. S. Wales, and 

 4 specimens labelled M. nigrans fitzroyensis from Lillesmere 

 Lagoons, Burdekin R., Queensland. 



A thorough examination of these specimens shows that they 

 are referable to two distinct species, easily distinguished by 

 the length of the praedorsal space and the length of the prae- 

 maxillaries. 



Richardson's description of M. nigrans is based upon a 

 specimen, which had been collected near Port Essington in Arn- 

 hem Land. When compared with the dimensions of the speci- 

 mens collected by Dr. Dahl, the measurements published by 

 Mr. Richardson (Ann. Mag. Nat. Hist., vol. IX, 1843, p. 181), 

 are not quite in agreement, as may be seen from the table below: 





Length 



Height 



Head 



Eye 



Eye 



Praedorsal 





(s. c.) 



in 



in 



m 



m 



space in % 





in mm. 



length. 



length. 



head. 



snouK 



of length. 



Richardson's 















type 



68 



3.6 



4.1 



3.9 



1.0 



50.0 



Dahl coll. 



63 



2.4 



3.7 



3.5 



1.0 



48.4 



- — 



75 



2.4 



3.6 



3.5 



1.2 



48.7 



The most striking difference is the relative height of the 

 body in Mr. Richardson's specimen and in those before me. 

 According to the measurements published in Richardson's paper 

 the height of the body is contained 3,6 times in the body-length 

 (s. c.) in the type specimen, while I in my specimens never 

 found this proportion reach more than 2,9. lean however, hardly 

 believe, that in nearly the same district two different races occur, 

 the chief difference of which should be only a difference in height. 

 Evidently the type specimen is an exceptionally low individual. 



