REVISION OF THE GENUS EUASTACUS 
9 
that date, the name sermtus has been applied by most authors 
to each of the various species of spiny crayfishes found in the 
rivers of eastern Australia. 
In 1898 Faxon (7) pointed out that the name Cmicer 
serratiis was preoccupied, having been used by Forskal in 
1775 for the crab now known as Scylla sermtus; he reinstated 
Heller’s name Astacoides spinifer. In the same paper he 
listed four of the other previously described forms, mention- 
ing that he had not seen examples of them, but, from the 
descriptions and figures, he considered each of them, with the 
exception of iiobiUs, synonjunous with spinifer. 
McCoy (17), described and figured as Astacoides serratus 
(Shaw), the species found in the Murray River, and included 
as synonjTiis spinifer and armatus. In a later paper (18), he 
described as Astacopsis serratus var. yarraensis the form 
found in the Yarra and adjacent rivers. 
Smith (29) included all described species under serratus, 
which he considered one large variable species, although he 
admitted that the various forms differed markedly from each 
other. In the same paper he described as Astaco)>sis kershawi 
the form found in the Moe River, Victoria ; this name is shown 
herein to be synonymous with nohiJis. 
McCulloch (19) placed as one large variable species, 
serratus, all the crayfishes from the INIurray River in Victoria, 
South Australia and Xcw South Wales; the Yarra River, 
Victoria ; from Gippsland, Victoria ; from numerous localities 
in New South Wales; and from Stanthorpe, Queensland. He 
separated as a distinct variety Astacopsis serratus var. 
hirsutus, a very hairy form from the Kangaroo River, New 
South Wales. 
In 1936 (2) in a revision of tlic Austi’alian members of the 
family Parastacidae, the genus Euastacus was erected for the 
Australian species previously contained in the genus Asta- 
copsis. In that paper the name serratus was assigned to the 
species found in the Murray River and its tributaries in 
Victoria, New South Wales and South Australia. This species 
was made the genotype of the new genus. At the same time, 
hirsutus was retained as a variety of serratus, and yarraensis 
was raised to full specific rank; nohilis was reinstated for the 
form found in the coastwise rivers in Victoria and New South 
Wales, with kershawi retained as a sub-species, inhabiting 
various coastwise rivers in Victoria. 
Since the pulilication of that revision, extensive enquiries 
have been made into the range of the genus, and a considerable 
number of specimens from numerous localities have been 
