FRESHWATER AND LAND CRAYFISHES OF AUSTRALIA 
7 
ingly when approached, and attack any object placed near 
them. Except in the size of the abdomen and the position of 
the genital openings there are no external differences between 
the sexes, though the abdomen of the female is generally 
broader and longer than that of the male, especially in some 
terrestrial species. 
Species of Euastacus , Cher ax and Engaeus kept alive in 
observation tanks were fed on earthworms, raw meat, fish and 
tadpoles, all of which were torn to pieces by the chelate pereo- 
pods before being eaten. Examination of stomach contents 
shows that they also swallow mud and debris of the rivers, 
etc., in which they live. 
Fully-grown specimens range in length from about 2 inches 
( Pseudengaeus ) to 16 inches ( Euastacus and Astacopsis). 
The largest of all known freshwater crayfishes belong to the 
two last-named genera. Specimens of E. nohilis (Dana) 
from the Thomson River, Victoria, weighed 5 lb. and meas- 
ured 16 inches f rom the tip of the rostrum to the end of the 
telson; Smith records from Tasmania a specimen of Asta- 
copsis that measured 16 inches and weighed 8 lb. Except in 
the large spiny or tuberculate species, there is little difference 
between immature and mature specimens of one species. 
Immature specimens of spiny species are comparatively free 
from spines and they gradually acquire the adult armature 
with each successive moult. Immature specimens of known 
species have been described as new species on several 
occasions. 
My thanks are due to Dr. Isabella Gordon, Dr. W. T. 
Caiman and W. E. Barnett, of the British Museum, for com- 
paring specimens with the type material of Gray, and for the 
loan of specimens; to the various museums and institutions 
in Australia that loaned or donated material ; to Mr. R. M. 
Murray, of Mt. Lycll, Tasmania, who collected specimens of 
Astacus tasmanicus Erichson ; to Miss II. Alexander, Mr. A. 
Blain and Mr. E. Nelson for collections of Western Australian 
species; to numerous other collectors for material; and to 
Mr. K. A. Lodewyckx, of the Public Library of Victoria, who 
translated papers by Erichson, von Martens and Hess. 
Tribe ASTACURA. 
Definition of the tribe (after Huxley, “The Crayfish,” 
1880, p. 254) : 
“Multicellular animals provided with an alimentary canal and with 
a chitinous cuticular exoskeleton; with a ganglionated central nervous 
