252 



Gen. 51. Cytherois, G. W. Muller, 1884. 



Generic Characters. Shell, as a rule, less compressed than in the pre- 

 ceding genus, but rather thin and fragile, of more or less elongate shape, with 

 the inner duplicatures rather broad, marginal zone however very narrow through- 

 out. A single well-developed eye always present. Anterior antennae with the 

 distal segment of the basal part narrow cylindrical in shape, terminal part 

 longer than this segment and composed of 3 joints. Posterior antennae com- 

 paratively robust with the penultimate joint distinctly subdivided, but without 

 any setiferous ledge in front, last joint with a single apical claw accompanied 

 behind by a very small bristle. Oral cone rather massive and directed down- 

 wards, terminating in a somewhat imperfect sucking disk. Mandibles very 

 strongly built and highly chitinised, with the masticatory part not at all 

 incurved and gradually tapered to a blunt point exhibiting inside slight traces 

 of cutting teeth; palp slender and of rather feeble consistency, with the proxi- 

 mal joints wholly coalesced, terminal joint falciform curved and densely seti- 

 ferous, vibratory plate rudimentary. Maxillae provided at the end with 4 densely 

 crowded narrow digitiform lobes, the outermost one representing the palp; 

 vibratory plate comparatively short, with 2 deflexed setae at the base. Legs 

 rather thin and of moderate length. Caudal lamellae very small, with one or 

 2 short bristles. Copulative appendages of male with the basal part large and 

 expanded, terminal part however comparatively poorly developed, lamelliform. 



Remarks.- This" genus, established in the year 1884 by G. W. Muller, 

 is nearly allied to Paradoxostoma, to which its species had indeed formerly 

 been referred, but differs very notably in the powerful development of the 

 mandibles and in the somewhat incomplete sucking disk on the extremity of 

 the oral cone. 3 species referable to this genus will be described in the sequel. 



140. Cytherois Fischeri, G. O. Sars. 



(PI. CX1V). 



Paradoxostoma Fischeri, G. O. Sars, Oversigt af Norges marine Ostracoder, p. 96. 

 Syn: Cytherois virens, G. W. Muller. 



Specific Characters. Female. Shell, seen laterally, oblong subtriangular 

 in shape, scarcely higher behind than in front, greatest height in the middle 

 and nearly equal to half the length, dorsal margin boldly arched, almost 

 angularly bent in the middle, and sloping rather steeply both in front and 





