CLETODES. 91 



form, and dividing at the extremity into one short and 

 one or two very long, lash-like branches ; first foot 

 much shorter than the rest. Basal joint of the fifth 

 pair (fig. 11) small, but produced into a long inner 

 segment, which has a ciliated inner margin and three 

 stout apical setas, and reaches nearly as far as the 

 end of the second joint ; second joint elongated, 

 narrow, bearing three stout, curved, marginal seta3, 

 and two at the apex. In the male (fig. 12) the two 

 branches are of nearly equal length, very narrow, 

 simple, the external branch bearing one, the internal 

 two, long apical setse. Caudal -segments short, but 

 longer in the male than in the female (?) ; seta3, one 

 on each segment, scarcely longer than the segment 

 itself. Length, -g^rd of an inch ('77 mm.). 



I have included in this description the form which, by 

 Mr. Robertson and myself, was noted (in our * Report 

 of Dredging on the Coasts of Durham and Yorkshire ') 

 as a new species under the name Cletodes pectinata. 

 A re-examination of these specimens leads me to think 

 that there is no sufficient reason to separate them 

 from the previously described species, though it is 

 certainly very difficult to decide in these minute and 

 nearly allied forms as to how much latitude must be 

 allowed for variation. There occurs not unfrequently 

 a form with very long and slender caudal rami almost 

 as long as those of C. longicaudata which, except for 

 this peculiarity, I am unable to distinguish from C. 

 limicola. The difference is certainly not a sexual one, 

 as both forms are to be seen in the adult oviparous 

 females. For the present I am content to note the 



