28 FRESHWATER AND LAND CRAYFISHES OF AUSTRALIA 
Over 400 specimens from all the above-mentioned localities 
were examined. 
This species is extremely variable, particularly in the great 
chelae, interantennal spine and rostrum. In a series of two 
hundred specimens from a quarry hole at Hawthorn, Victoria, 
the great chelae vary in length and breadth at all stages of 
growth. Several examples, two inches long, have very short 
stout chelae with the dactylus less than half as long as the 
propodus ; other examples of the same size have long, slender 
chelae, with the dactylus one-half as long as the propodus. 
Adult specimens, five and six inches long, show similar varia- 
tions. The interantennal spine in some is short and broad, 
with a blunt point ; in others short, broad and rounded ; the 
outer margin may be serrated, or smooth. The rostrum varies 
greatly in breadth in examples of all sizes, the spines at the 
apex are obsolete in several specimens, and three have a spine 
on one side only of the apex. 
Specimens from Barron Falls, Queensland, have the long, 
slender chelae and broad rostrum, identical with the Haw- 
thorn examples. Specimens from Charlotte Waters, Central 
Australia, have no spines at the apex of the rostrum, but are 
otherwise identical with the type specimens. 
Cherax albidus sp. nov. 
(PI. I, fig. 4; PI. VI, fig. 24.) 
Length of average adult specimen, 137 mm. 
Rostrum twice as long as broad at base, reaching almost to base of third 
segment of first antennae ; apex blunt, carinae blunt reaching almost to apex ; 
lateral carinae blunt, ending in a rounded boss. 
Squame of each second antenna broad anteriorly, terminal spine short and 
sharp, reaching to base of third segment of first antenna. Interantennal spine 
short and broad, sharply pointed. 
Carapace shorter than abdomen, broader than high ; areola fairly broad. 
Anterior of carapace smooth, posterior densely, minutely, punctate. 
Sternal keel blunt, slightly rounded, produced to a sharp, backwardly- 
directed spine below great chelae; first two pairs of lateral processes obsolete, 
third pair small and flat, each with a conspicuous opening; posterior pair 
larger, slightly grooved, each with a conspicuous round opening on upper 
margin ; processes between fourth pereopods flattened. 
Telson with a spine on each lateral margin at junction of membranous 
portion ; inner rami of uropods each with a median spine and an outer 
lateral spine at junction of membranous portion ; outer rami each with several 
sharp spines along transverse suture. Lobes at base of uropods with upper 
lobe rounded. 
Great chelae very long and stout ; propodus three times as long as broad, 
with a few scattered punctures, upper margin with three feeble tubercles 
posteriorly, lower margin smooth, cutting edge with one small tubercle ; 
