108 NOTES ON THE AUSTRALIAN AMPHIPODA, 



Cyrtophium PARASITICUM. 



(Plate XVJI., figs. 1-7.) 



Cyrtophmm parasiticum, Haswell, Proc. Linn., Soc, N.S.W., 

 Vol. IV., p. 274, pi. XII., fig. 1. Cat. Aust. Crust., p. 271. 



The superior antennje of this species are nearly as long as the 

 head and pei'eion ; the first joint of the peduncle is a little shorter 

 than the head and stout, the second more than twice as long, 

 narrower, the third a little shorter and narrower than the second ; 

 the flagellum is equal in length tc the last joint of the peduncle, 

 composed of four joints, the first more than half the length of the 

 whole flagellum, the others small. The lower antennae are very 

 large, as long as the head and body, and are very stout ; the fifth 

 segment of the peduncle is a little longer than the fourth ; the 

 flagellum is a little more than half the length of the fifth segment 

 of the peduncle, and exhibits very slight traces of division into 

 nine joints ; the extremity is ornamented with a fasciculus of 

 short spines which ai'e very slightly bent or hooked at the ends. 

 The anterior gnathopods have the propus ovate, the palm even, 

 slightly convex, sepai'ated off from the rest of the border by being 

 more prominent. The posterior gnathopods are large ; neither 

 merus nor carpus have tooth-like processes ; the propus is narrow, 

 ovate, constricted proximally ; the palm with a prominent acute 

 tooth at its proximaj end (the middle of the propus), separated by 

 a deep excavation from the distal portion, which is minutely denti- 

 culated ; the dactylus is about three-fourths of the length of the 

 propus. The protopodite of the fourth pair of pleopoda projects 

 beyond the extremity of the telson ; the rami are long and narrow, 

 the outer being much shorter than the inner, the inner is obscurely 

 serrated, and both are tipped with straight spines. The fifth 

 segment has no appendages. 



The posterior gnathopoda of male specimens vary within certain 

 limits, the palmar tooth being more or less prominent, and the 

 propus being sometimes bordered with long hairs, sometimes not 



