so 



Gen. Mesocletodes, G. O. Sars. 



Remarks. This genus was established by the present author to include 

 the form described by Scott as Cletodes irrasa, which I found differed in 

 certain points so materially from the other members of the present family as 

 more properly to be separated from them generically. The validity of this 

 genus I am now -enabled to confirm by adding 3 other species which are 

 evidently congeneric with the above-mentioned form. 



65. Mesocletodes monensis, (Thompson). 



(PI. LIV). 



Cletodes monensis, I. C. Thompson, Proc. & Transact, of Liverpool Zool. Society, 



Vol. VII, p. 200, PL XXXIV. 



Specific Characters. Female. Body comparatively more slender than 

 in the type species and about of equal width throughout; all the segments 

 minutely denticulate at the hind edge. Cephalic segment about the length of 

 the 3 succeeding segments combined and somewhat contracted in its anterior 

 part; rostral projection well defined and slightly curved downwards, with the 

 tip acutely pointed; dorsal face of the segment somewhat vaulted and ex- 

 hibiting behind the middle a very conspicuous horn-like process curved back- 

 wards. Urosome about the length of the anterior division; genital segment of 

 moderate size and imperfectly subdivided in the middle; last segment nearly as 

 large as the 2 preceding segments combined, and having the anal opercle some- 

 what prominent and armed dorsally with 2 successive denticles, the posterior one 

 rather coarse and pointing backwards. Caudal rami slender and narrow, though 

 not nearly attaining half the length of the remaining part of the tail; outer 

 edge with 2 small bristles, the one attached at a short distance from the base, 

 the other close to the end; dorsal seta issuing somewhat in front of the middle; 

 apical setae very unequal, the middle one much the largest and about as long 

 as the ramus, the innermost extremely small. Anterior antennae rather slender, 

 nearly attaining the length of the cephalic segment, and composed of 7 sharply 

 defined joints clothed with comparatively short, partly spiniform setae; 2nd joint 

 much the largest; antepenultimate joint about the length of the last 2 joints 

 combined. Posterior antennae with the outer ramus very small, bisetose. Oral 

 parts agreeing in structure with those in the type species. Natatory legs like- 

 wise rather similar, though comparatively somewhat less slender; inner ramus 

 very small, but, as in the type species, distinctly biarticulate. Last pair of 

 legs confluent in the middle; distal joints narrow linear in form, not dilated 



