Marine Copepods from Western Australia, Series II. 
209 
11.— MARINE COPEPODS FROM WESTERN AUSTRALIA 
SERIES II. 
TWO PELAGIC COPEPODS FROM COCKBURN SOUND. 
By W. S. Fatrbridoe, B.Sc. 
Road 1 4th April, 1942 ; published 27 March, 1944. 
The species described were found in some plankton hauls made a few 
miles south of Fremantle in Cockburn Sound, about midway between Garden 
Island and the mainland. The maximum depth of water in the area is 20 
metres. 
Order CALANOIDA. 
Family CENTROPAGIDAE Sai-s, 1902. 
Genus CENTROPAGES Kroyer, 1849. 
A large number of ne\^' species ha\ e been described since tViis genus M'as 
summarised by Giesbrecht and Schmeil (1898). Unfortunately, the author 
has been unable to study' the descriptions of C. longicornis (Mori, 1932) and 
C. jjunticus (Karawiew', 1895). 
Centropages australiensis sp. nov. 
Occurrence. — Regularly found, sometimes forming a considerable pro- 
portion of the catch ; males and females in about equal numbers. 
Female. — Length, 1*4-1 *6 mm. 
The mouth parts agree with those figured for C. typicus (Kroyer, 1848) 
by Giesbrecht (1892, Fauna und Flora des Golfes von Neapel) and Sars (1900, 
An Account of the Crustacea of Norway'), 
The fifth leg differs from C. typicus in the endopod, the second segment 
being as long or longer than the terminal and distinctly narrowed at the base, 
and the basal segment broadened distally. The second abdominal segment 
is very long compared with the genital and anal segments ; the proportions 
of the abdominal segments are 23 : 34 : 10 j 18. The genital segment bears 
only' two spines, one dorso-lateral and one ventro-lateral, both on the left 
side, the latter being very small ; the second segment bears a hooked knob 
on its right side. The fifth thoracic segment is only slightly asymmetrical, 
the left side being the larger. 
Male. — Length, 1*4-1 *5 mm. 
The first antenna has a distinct .spine on segments 15 and 10 (Sars does 
not figure a spine on segment 15 for G. tyjjicu.^, and Giesbrecht indicates a 
minute one) ; thei’e is an incomplete division between segments 22 and 23 
(as indicated by Giesbrecht for C. typicus, but vSars show's a complete division). 
The other mouth parts agree with those for C. typicus. 
The swimming legs appear to be ty'pical : Giesbrecht (1898) says of 
C. typicus that the right exopods of legs 3 and 4 bear a “ vergrosserten Aussen- 
randdorn ” on the second segment ; this is noticeable in the present species. 
The fifth leg differs markcdl}' bum C. typicus in that the basal portion of the 
chela is much narrower, resembling the type found in C. hamatus (Lilljeborg, 
1853) ; and the proximal segment of the chela extends beyond the “ thumb 
and is but slightly hooked at the tip. The abdomen agrees with 0. typicus. 
The spines of the last tlioracic segment are asymmetrical, the right being 
much smaller than the left. 
k 17/43. 
