Length of female amounting to 2.50 mm. 



Remarks. The present form is closely allied to the type species, but of 

 smaller size, and moreover easily distinguishable by the somewhat different 

 shape of the shell, the posterior corner of which is in both sexes considerably 

 more exerted. In the female, moreover, the rostral part looks rather different, 

 being still more strongly procumbent and transversely truncated at the end. 



Occurrence. This is a true deep-water form, occurring, as a rule, only 

 in depths below 100 fathoms. I have met with it occasionally in several places 

 on the Norwegian coast, from the Christiania Fjord up to the Lofoten islands. 



Distribution. West coast of Sweden, Beeren Island, Iceland, Atlantic 

 Ocean, down to 430 fathoms. 



Gen. 3. Asterope, Philippi, 1840. 



Syn: Cylindroleberis, Brady. 

 Copechaete, Hesse. 



Generic Characters. Sexual dimorphism rather strongly marked. Shell 

 in female of rather firm consistency and more or less oblong or elliptical in 

 shape, wijh the frontal incisure of the valves very deep and narrow, arched 

 over by -the rather large and evenly vaulted rostral part. Shell of male much 

 thinner and considerably differing in shape from that in female. Eyes in most 

 cases well developed in both sexes. Frontal tentacle slender. Anterior antennae 

 6-articulate and on the whole built on the same type as in the other Cypri- 

 dinidae, though having the outer part in female broader, with the joints pro- 

 nouncedly compressed and clothed with upturned ciliated setae generally projecting 

 from the shell in front; last joint small and provided, in addition to the setae, 

 with a short claw-like spine, seta attached to the posterior corner of antepenulti- 

 mate joint in both sexes distinctly sensory; same antennae in male transformed 

 in a much similar manner to that in the genus Philomedes, 2 of the apical 

 setae being enormously prolonged. Posterior antennae of quite normal structure, 

 with the inner ramus in female very small and in male distinctly prehensile. 

 Anterior lip small, lobular at the end. Mandibles with the masticatory process 

 very slender, falciform, and ascending along the inner face of the basal part 

 towards the gullet; palp rather powerfully developed, with the joints broad 

 and compressed, the 1st produced at the base below to a conical recurved 

 pocess clothed with several spiniform setae; last joint armed with a straight, 

 scarcely unguiform spine accompagned by a number of setae. Maxillae and 

 maxillipeds rather feeble in structure and without any distinctly defined mastic- 



