12 
REVISION OF THE GENUS EUASTACUS 
Systematic Descriptions 
Key to species of EUASTACUS Clark. 
Rostrum very long and broad, apex long and sharp, carinae with sharp spines. 
Second antennae reaching to, or beyond, telson. 
Great chelae long and slender ELONGATUS sp. nov. 
Second antennae reaching third or fourth abdominal segment. 
Great chelae long and very stout . . . . ARMATUS (von Martens) 
Great chelae short and stout YARRAENSIS (McCoy) 
Rostrum long and broad, apex short, carinae tuberculate or with blunt spines. 
Two rows of short broad spines or tubercles on each branchiostegite ; 
abdomen spinose SERRATUS (Shaw) 
Carapace and abdomen without large spines or tubercles; entire animal 
densely hirsute HIRSUTUS (McCulloch) 
Rostrum short and broad, apex blunt, carinae tuberculate. 
Abdomen with several rows of small sharp spines on each segment 
SUTTONI sp. nov. 
Abdomen without spines or tubercles except on lateral margins 
FLECKERI (Watson) 
Abdomen with three rows of sharp spines and a large rounded ridge on 
dorsum of each segment NOBILIS (Dana) 
Abdomen with two rows of spines and a flattened ridge on dorsum of 
each segment BISPINOSUS sp. nov. 
Eiiastacus dongatus sp. nov. 
Plate I. 
Enastacus serratiis (Shaw), Clark, Mem. Nat. Mus. Viet., x, 1936, p. 12, 
pi. 1, fig. 1 ; pi. 2, fig. 12 ; Victorian Year-Book, 1936-37, p. 34. 
Length of average adult specimen 300 mm. 
Rostrum very long and broad, reaching end of third segment of second 
antennae, apex long and sharp; lateral carinae obtuse, each with three or 
four sharp spines. A blunt, punctate carina ending in a small sharp spine 
at base of each carina, and a small sharp spine on a large rounded boss 
posterior-laterally to it. 
Second antennae long and slender, reaching beyond end of telson. Squame 
smooth, inner lobe short and broad, terminal spine long, stout and sharp. 
Interantennal spine triangular, apex blunt, lateral margins serrated. 
Carapace more than twice as long as broad, broader than high, longer than 
abdomen. Branchiostegites studded with numerous small tubercles, and 
several sharp spines in an irregular row on upper margin. 
Abdomen spinose. First segment with a long stout sharp spine on each 
lateral lobe, a short stout blunt spine above each lateral spine. Second segment 
with two short slender sharp spines on each lateral margin; a long stout 
sharp spine and a large broad, forwardly directed, sharp spine above the 
lateral spines. Third segment with a slender sharp spine at each lateral 
margin; a long stout sharp spine, directed slightly forwards, above each of 
the lateral spines. Fourth and fifth segments each with a short slender sharp 
spine at each lateral margin; a short slender sharp spine, a long stout 
forwardly directed sharp spine, and a large broad forwardly directed sharp 
spine above each lateral spine. Sixth segment with a very short sharp spine 
near each lateral margin; a short sharp backwardly directed spine above 
each lateral spine. 
Telson broad, slightly longer than broad, almost completely divided by a 
