85 



not specially contracted at the end, which is acute and 

 slightly bent downwards. 



The epistome is without anterior crest; the sides thin 

 away and recede more than in the two preceding species.. 



The antennules have the nagellum with 10 joints, that 

 of the antenna with 16 joints. 



The mandibles have the group of setae near the molar 

 process, as in Z. venosa and Z. excavata. 



The mouth parts, legs, and pleopods resemble those of 

 the preceding species. The appendix masculina is long ; its 

 apex bears a few setules. 



The uropods are broad and lamellar, the inner ramus 

 not reaching quite to the end of the abdomen, the outer one 

 a little beyond. 



A young male, apparently of this species, has the end 

 of the abdomen much more rounded, the uropods not reach- 

 ing as far as it. 



Females of this species I have not observed. 



Gulf St. Vincent. Two adult male and one young male 

 specimens. 



Group Eubranchiat^:, Hansen. 



Genus Cerceis, M. Edw. 



Cerceis trispinosa, Haswell. PI. xxiv., hgs. 9 to 15. 



Cymodocea trispinosa, Haswell, Proc. Linn. Soc., N.S.W., 

 vi., p. 189, pi. iii., fig. 7. 



The bod}^ of the male has the usual shape of species of 

 this genus. The head is gradually declivous anteriorly with- 

 out a distinct transverse ridge. The rostral process is well 

 marked, "and not fused with the epistome. 



The segments of the thorax do not differ much in length ; 

 their epimeral plates are large, and are marked off from their 

 respective segments by a faint longitudinal groove. That of 

 the seventh is hooked behind. 



The anterior portion of the abdomen is short, and has 

 a small median tubercle on its posterior border. There are 

 also besides the median larger tubercle of the posterior por- 

 tion two smaller tubercles side by side just above it ; this 

 portion is sparingly granular and setose. The posterior notch 

 is deeply cut, narrow, and as its median process is only 

 slightly raised above the lateral processes the channel below 

 is not very deep. 



The epistome is broad, apically acute, its lateral limbs 

 much spread out, their extremities each with two small 

 tubercles; there is also a small tubercle at the base of each 

 limb. The labrum is rather large. The basal joint of the 

 antennule is deeply notched, its distal anterior limb is 



