56 

 6. Argilloecia conoidea, G. O. Sars, n. sp. 



(PI. XXV) 



Specific Characters. Female. Shell, seen laterally, very narrow, oblong 

 conoid in shape, greatest height in the middle and scarcely exceeding 2 /5 of 

 the length, dorsal margin gently arched and sloping with a quite even curve 

 to the hind produced corner, ventral margin distinctly sinuated in the middle, 

 anterior extremity broadly rounded, posterior conically tapering to an obtuse 

 point lying below the longitudinal axis; seen dorsally, oblong ovate in out- 

 line, with the greatest width behind the middle and only little exceeding Va 

 of the length, anterior extremity more pointed than the posterior. Valves rather 

 pellucid, with the surface smooth and glabrous; inner duplicatures remarkably 

 broad and exhibiting a somewhat irregular highly chitinised marginal zone, 

 which in front projects in 2 opposit sharp corners, between which the inner 

 edge of the duplicature is suspended. Structure of the several limbs very like 

 that in the typical species. Posterior legs, however, only provided at the tip 

 with 2 setae of unequal length, the shorter one distinctly pectinate. Caudal rami 

 comparatively narrower than in the preceding species and somewhat curved. 



Male resembling in general appearance that of the type species, but of 

 considerably smaller size, and having the shell comparatively still narrower, 

 with the posterior extremity more produced. Some of the setae attached to 

 the 2 pairs of antennae, as in that species excessively prolonged and recurv 

 in the very same manner. Prehensile palps of maxillipeds with the propodu 

 almost quadrate in form and armed at the end inside with a short spine accom- 

 panied by 2 small bristles, dactylus of moderate size and slightly curved 

 Copulative appendages rather slender and somewhat irregularly expanded 

 the end. 



Colour not yet ascertained. 



Length of adult female 0.59 mm, of male 0.50 mm. 



Remarks. Though agreeing pretty well in the essential structural details, 

 present species may readily be distinguished from the preceding one by th 

 rather different shape of the shell, especially in the female. It is also of rath 

 inferior size. In its general appearance it looks rather like some of the Medite 

 ranean species recorded by G. W. Miiller; but I have been unable to ascertain 

 its identity with any of them. 



Occurrence. 3 specimens only of this form, an adult female and 2 males, 

 have as yet come under my notice. They were picked up from a gatherin 

 taken at Risor, south coast of Norway, from moderate deeps. 





