10 
FRESHWATER AND LAND CRAYFISHES OF AUSTRALIA 
Abdomen without spines or tubercles, lateral margins rounded. Lateral 
lobes on first abdominal somite small and rounded. Sternal 
keel narrow, continued across the obsolete posterior pair of 
lateral processes GEOCHARAX gen. nov. 
Stems of podobranchs without lateral wing-like expansion. 
Second antennae inserted at the side of the first. 
Abdomen without spines or tubercles, except on pleura of second 
somite; lateral margins round or pointed. Lateral lobes on 
first somite large and rounded . . . . ASTACOPSIS Huxley 
Second antennae inserted under the first. 
Abdomen without spines or tubercles, lateral margins rounded. 
Pleurobranchs present, gill formula 21 -f- epr. 
Sternal keel narrow, posterior pair of lateral processes single, large 
and grooved. First abdominal somite without lateral lobes 
ENGAEUS Erichson 
Sternal keel broad and swollen, posterior pair of lateral processes 
appearing double. First abdominal somite without lateral lobes 
PSEUDENGAEUS gen. nov. 
No pleurobranchs present, branchial formula 12 + 5r + epr. First 
abdominal somite with lateral lobes large and rounded 
PARASTACOIDES gen. nov. 
Genus EUASTACUS gen. nov. 
Cancer Sbaw, Zool. of New Holland, i, p. 21, pi. 8, 1794. 
Astacoides Dana, U.S. Explor. Exped., Crust., pt. i, p. 526, 1852; 
Heller, Reise Novara, Crust., p. 102, 1865; von Martens, Ann. Mag. 
Nat. Hist., ser. 3, xvii, p. 359, 1866; McCoy, Prodromus Zool. 
Victoria, i, 1879, p. 17. 
Aslacus McCoy, Ann. Mag. Nat. Hist., ser. 3, xx, 1867, p. 189; Pleller, 
Reise Novara, Zool., ii, pt. 3, Crust., 1865, p. 100; von Martens, 
Monats. Akad. Wiss. Berlin, 1868, p. 615. 
Astacopsis Haswell, Cat. Austrl. Mus., Crust., p. 175, 1882; Spence- 
Batc, “Challenger” Reports, xxiv, 1888, p. 195; Smith, Proc. Zool. 
Soc. Lond., p. 154, 1912; Faxon, Mem. Mus. Comp. Zool., xl, 8, 
p. 402, 1914; Faxon, Proc. U.S. Nat. Mus., xx, 1898, p. 669; 
McCulloch, Rec. Austrl. Mus., No. 11, 1917, p. 237 ; Hale, Handbook 
Crust. Sth. Austrl., 1927, p. 75. 
Carapace furnished with large spines or tubercles; rostral carinae tubercu- 
late or spinous. Cervical groove deeply impressed, rounded. 
Abdomen usually with three or more rows of spines or tubercles laterally, 
lateral margins rounded. First somite with lateral lobes large and rounded. 
Telson more or less completely divided by a transverse suture, membranous 
posteriorly. 
Second antennae set at the side of the first ; squames large. Upper lip 
long and narrow, straight or somewhat concave medianly. 
Vas deferens on simple short papillae on coxae of fourth pereopods. 
Stems of podobranchs each produced into a broad wing-like expansion 
(Plate I, fig. 1), covered by numerous long setae, terminated by sharply 
recurved hooks. Last posterior arthrobranch small. Gill formula 21 -)- epr. 
Genotype Cancer serratus Sliaw. 
