FRESHWATER AND LAND CRAYFISHES OF AUSTRALIA 25 
Smith (1912) erected a new genus Parachaeraps for a single 
species, Astacus bicarinatus Gray, which previously was 
included in the genus C hemps. The reasons for erecting the 
genus are rather vague, as he states that bicarinatus does not 
differ very strikingly from species retained in Gheraps. The 
main reason, apparently, was to demonstrate his theory of the 
evolution of the Australian crayfishes, but in the paper with 
E. H. J. Schuster (1913) he refutes his original theory, intro- 
ducing another in which this species is not important, making 
the genus no longer necessary from this point of view. Apart 
from that, the generic characters given do not apply to the 
specimens, now in the National Museum, upon which he 
founded the genus. 
The chief generic character given is as follows : 
“The distance between the tip of the rostrum and the cervical suture 
is shorter than between the cervical suture and the posterior border of 
the carapace.” 
While in Chaeraps: 
“The distance between the tip of the rostrum and the cervical suture 
is distinctly longer than that between the cervical suture and the posterior 
border of the carapace.” 
Over four hundred specimens, including Smith’s types, 
have been examined, and in all the distance between the tip 
of the rostrum and the cervical suture is at least one and one- 
third times as great as the distance between the cervical suture 
and the posterior border of the carapace. 
Furthermore, the specimens on which Parachaeraps is 
based are not, as stated, Astacus bicarinatus Gray. 
Gray (1845) described and figured Astacus bicarinatus 
from material collected at Port Essington, Northern Terri- 
tory. Two pages preceding the description he gave an account 
of a drawing, received from Mr. Eyre, of a crayfish called by 
the natives eu-kod-ko or koon-go-la ; he applied no name to 
this species, which he considered to be nearest his quinque- 
carinatus. Subsequent authors, however, have treated the 
drawing as synonymous with A. bicarinatus, although Faxon 
(1898, p. 673) noted that the description and figure do not 
apply very closely to the species commonly known by this 
name. 
The types of A. bicarinatus received on loan from the 
British Museum show that Gray’s species is identical with 
that described by Smith as Chaeraps intermedins. The com- 
mon yabby (apparently the original of the drawing of the 
eu-kod-ko) on which Smith founded Parachaeraps , is distinct 
from bicarinatus and has not otherwise been named. 
