Rev. T. R. R. Stebbing on Gastrosaccus spiniferus. 115 



The large epimeron of the first pleon-segment, which is so 

 characteristic in the females of this genus, differs from the 

 corresponding part as figured by Sars for Gastrosaccus sanc- 

 tus and G. Normanij in that its hinder point of attachment is 

 not at the hinder lateral angle of the segment, but very near 

 to its front margin, whence its edge slopes back to an angular 

 termination at the hinder lateral angle of the second segment. 

 Its shape, instead of being oval, might rather be described as 

 an irregular lozenge-form. The curved lower margin is 

 folded under the marsupium ; the front margin is microscopi- 

 cally serrate. It may be well to notice that the extreme 

 transparency of the parts makes it very difficult to follow the 

 overlapping outlines of this epimeron, the carapace, and the 

 marsupium. Seen from below, the marsupial pouch ends 

 anteriorly in an equilateral triangle. With the notable dis- 

 tinction already mentioned, the shape of the carapace and its 

 surface-markings bear a close resemblance to those described 

 by Prof. G. 0. Sars for G. sanctus. 



The eyes are black, with short, thick, cylindrical stalks, 

 without dendritic markings, bulging a little on the inner side ; 

 they project slightly beyond the edges of the carapace. 



The upper antennas have the first joint of the peduncle long, 

 stout, and cylindrical ; on the outer anterior edge it ends in a 

 minute process. The second joint is short, longer on the 

 inner side, where it has two small hairs, than on the outer, 

 along which are ranged three incurved spines, of which the 

 foremost is the largest. The third joint is half the length of 

 the first, and not quite twice that of the second, with its 

 anterior edge sharply truncate between the two filaments, 

 within the base of the outer one directing forwards a little 

 conical process. The filaments (as, indeed, the whole of these 

 antennas) bear the closest likeness to those of G. sanctus ; in 

 that species, however, the spines of the second joint of the 

 peduncle are figured as straight, not incurved. 



The scale of the lower antennas reaches nearly to the end 

 of the peduncle ; it has its outer edge straight and smooth, 

 the spine-like termination nearly level at its point with the 

 front of the rounded anterior margin, which, as well as the 

 inner margin, is closely set with long plumose setas. The pedun- 

 cle reaches nearly to the end of the second joint of the upper 

 antennas. The shape and ornamentation and the filament 

 agree with the descriptions of G. sanctus. The upper lip is 

 helmet-shaped, ending in a long thin spike ; it is dendriti- 

 cally marked. 



The palps of the mandibles have the first joint short ; the 



