NO. 5.] ACCOUNT OF THE SPECIES. 39 



penultimate one is but little smaller than the preceding segment, whereas the 

 last, or anal segment is very short. The caudal rami, or furca, are like- 

 wise rather short, being scarcely twice as long as they are broad. They 

 are finely ciliated inside, and obliquely rounded at the end, each carrying 5 

 densely plumous setae. Of these the 2 outer are attached to distinct ledges 

 outside the tip, whereas the remaining 3 orginate from the tip itself. The 

 middle apical seta, or the innermost but one, is much longer than the others, 

 and may attain to twice the length of the tail. As, however, these setae 

 are very brittle, it is rather unusual to find specimens in which they are 

 quite perfect. In addition to the above-mentioned caudal setae, a very deli- 

 cate unciliated bristle is found, as usual, on each of the rami, originating 

 from the inner corner, and lying above the others. 



No trace of eye could be detected in the alcoholic specimens; but it is 

 very probable that in reality it is present in the fresh state of the animal, 

 though of very simple structure, and easily destructible by the action of 

 the alcohol. 



The anterior antennae (see figs. 1 & 2) slightly exceed in length the 

 anterior division of the body, and are rather slender, gradually tapering some- 

 what distally. They are composed (see PI. VIII, fig. 1) of 23 articulations, 

 carrying in front scattered bristles of somewhat unequal length. As the 

 normal number of articulations in the Calanoids is 25, a fusion of some of 

 the articulations may be supposed to have taken place. It will also be found, 

 that 2 of the articulations, viz., the 2nd and the 8th, are of unusual size and 

 may both originally have represented 2 articulations. This being admitted, 

 the full number of articulations is made up. The penultimate articulation is 

 somewhat longer than the next preceding ones, and carries at the end, both 

 in front and behind, a rather strong seta. The last articulation is extremely 

 small, and is connected with the former along an oblique suture. It is pro- 

 vided at the tip with a fascicle of comparatively short bristles. 



The posterior antennae (fig. 2) are, as usual, each composed of a short 

 biarticulate basal part, and 2 differently formed rami. The distal joint of the 

 basal part is considerably larger than the proximal one, and carries at the 

 end anteriorly, 2 slender ciliated setae. The inner ramus is composed of 2 

 joints, the 1st long and narrow, linear in form, and carrying, at some distance 

 from the tip anteriorly, a single slender seta, the 2nd short, slightly bilobular 



