116 A Synopsis of the Recent British Ostracoda. 



the anterior long:, five-jointed, and dissimilar in the male and 

 female ; posterior very small and rudimentary. Post-abdomen 

 consisting of two snort, clawed laminse. Shell excessively 

 thin and flexible, almost membranaceous ; in general shape 

 approaching that of the Cypridinidse. 



Polycopiml — Both pairs of antennae natatory : the upper 

 simple ; the lower two-branched. Mandibular palp small, not 

 pediform. Two pairs of feet : the anterior natatory ; the pos- 

 terior branchial. Abdomen terminating in two short ungui- 

 ferous laminae. Eyes and heart wanting. Intestine forming 

 a simple sac. Shell thin, calcareous, not notched. 



Cytherellidj3. — Antennas very large; the upper multi- 

 articulate and geniculate ; the lower broad, two-branched, 

 much like the feet of the Copepoda. Mandibles very small, 

 bearing a large setose palp. Three pairs of legs, which are 

 scarcely pediform : the anterior two branchial ; the posterior 

 rudimentary. Abdomen terminating in two very small and 

 narrow spiniferous laminae. Ova and young borne under the 

 shell of the female. Yalves very unequal in size, not notched ; 

 structure very dense, hinge formed by a simple groove. 



It is impossible, in the necessarily restricted limits of a 

 magazine article, to give a detailed account of the specific 

 characters of all the British Ostracoda. I propose, however, 

 to indicate briefly the more important characters of the different 

 genera (a thing which has not yet been done with reference 

 to anatomical characters in this country), giving under each 

 genus a list of the British species belonging to it, and ap- 

 pending such remarks concerning them as may appear likely 

 to be of general interest, or helpful to those seeking for 

 special information respecting this interesting group of 

 Microzoa. 



Family — Cypeid.e. 



Genus Cypeis, Miiller. — Upper and lower antennae both 

 provided with a tuft of plumose filaments, the lower pediform. 

 Both pairs of jaws bearing branchial appendages. Second 

 pair of jaws in the male prehensile; in the female consisting of 

 a short lobe, a palp which terminates in three setae, and a 

 small branchial plate with six radiating respiratory setae. 

 Post-abdominal rami long and slender, having two terminal 

 curved claws and a small seta. Males provided with a 

 "mucous gland/' composed of a double cylinder beset with 

 radiating filaments. Shell mostly subreniform or ovate, and 

 of no great thickness. Inhabits fresh water. 



British Species. — C.fusca, Straus; incongruens, Eamdohr; 



