Fam. 1. CypHdinidae. 



Characters of the family. Valves of rather firm consistency, in some 

 cases roughly sculptured and highly calcareous, frontal incisure as a rule rather 

 deep and defined above by a more or less projecting rostral prominence. Two 

 compound stalked eyes generally present, and moreover an unpaired central 

 ocellus, from the lower face of which the frontal tentacle issues. Anterior 

 antennae in both sexes well developed, distinctly geniculate at the base, and 

 carrying at the end strong annulated setae, one of which, attached posteriorly 

 at some distance from the tip, is generally pronouncedly sensory. Posterior 

 antennae with the basal part trigonal or cordiform in shape, inner ramus bi- or 

 triarticulate, very small in female, and having none of the joints conspicuously 

 expanded, in male generally larger and prehensile. Mandibles with the mastica- 

 tory part imperfectly developed, palp strong, with a small exopodal appendage 

 at the end of the 1st joint anteriorly. None of the postoral limbs pediform, 

 the 2nd pair being always provided at the base with a broad semilunar vibratory 

 plate; penultimate pair closely juxtaposed, each terminating in a vertical, 

 broadly triangular lamella; last pair very peculiar, slender vermiform in shape 

 and highly flexible, curving upwards and bakwards within the shell, and armed 

 in their outer part with a number of peculiarly modified spines. Caudal lamellae 

 without any spine in front of the marginal claws. Copulatory appendages in 

 male symmetrical, more or less coalesced at the base. Ripe ova received within 

 the cavity of the shell for accomplishing their first (larval) development. 



Remarks. The type of this family is the genus Cypridina of M. Edwards, 

 to which in recent time several other genera have been added, more or less 

 differing from the type, though retaining most of the characteristic' features 

 of that genus. Of these features may be named the presence of compound 

 stalked eyes and a well defined central ocellus, the comparatively full deve- 

 lopment of the anterior antennae, the peculiar reduction of the masticatory part 

 of the mandibles, and finally the anomalous structure of the 3 posterior pairs 

 of limbs. Especially is the appearance of the last pair of limbs highly remark- 

 able and unlike that found in any other Ostracods. 



3 well defined genera referable to this family are represented in the 

 Fauna of Norway. 



