FRESHWATER AND LAND CRAYFISHES OF AUSTRALIA 51 
find it in 1868, and, according to McCulloch (1917), it was not 
in the Berlin Museum in 1914. 
Huxley (1878) raised the subgenus to generic rank, under 
the name Chaeraps. Various authors have referred several 
species to this genus, but all have a well-developed pleuro- 
branch on each of the fifth pair of legs, making their inclusion 
in Erichson’s genus impossible. McCulloch (1917) noted this 
fact, and considered intermedins Smith to be synonymous 
with preissii in spite of the fact that intermedins has gills on 
the fifth legs. 
The two species, A. tasmanicus (with gills on the fifth legs) 
and C. preissii (without gills on the fifth legs), have been 
identified only doubtfully by subsequent authors. One is thus 
forced to the conclusion that Erichson attributed the presence 
or absence of gills on the fifth legs to the wrong specimens. 
With this character reversed preissii becomes the specimen 
with the gills, and the genus Che rax then contains all the 
species hitherto doubtfully referred to it ; and the specimens 
which otherwise fit the description of tasmanicus Erichson 
(nec tasmanicus Smith) are identified with certainty. 
Family AUSTRO ASTACIDAE fam. nov. 
First abdominal segment devoid of appendages in both sexes. 
Podobranchs without either a bilobed plaited lamina or a lateral wing-like 
expansion. Epipods of first maxillipedes without branchial filaments. The 
fourth pereopods without gills. 
Each first antenna with the second flagellum small or absent. 
Carapace strongly vaulted posteriorly. Abdomen small. First somite 
without lateral lobes. Telson and uropods entirely calcareous, not divided 
by transverse sutures. 
Genus AUSTROASTACUS gen. nov. 
Carapace higher than broad, highly vaulted posteriorly. Abdomen small, 
swimmerets long ; first somite without lobes or spines. 
Telson and uropods entirely calcareous, without transverse sutures. 
First antennae each with either one or two flagella. Second antennae 
inserted below first. Upper lip short and broad. 
Sternal keel flattened or feebly raised. Vas deferens on simple short 
papillae on coxae of fourth pereopods. Posterior pleurobranchs absent. 
Podobranchs without wing-like expansions. 
Genotype Engaeus hemicirratulus Smith and Schuster. 
Key to Species of AUSTROASTACUS gen. nov. 
First antennae each with one flagellum 
HEMICIRRATULUS (Sm. and Sch.) 
First antennae each with two flagella CYMUS sp. nov. 
