RECENT BRITISH OSTRACODA. 



393 



Pamily 2. Cytherid^, 



a 



o g 



^ 



+3 a- ■ 

 a o 



P 

 -13 



Lower 



antennae 



4-jointed. 



Upper 



antennae 



5-jointed ; 

 last three 

 joints 



elongated, 

 their united 

 lengths more 

 than that of 

 the preceding 

 joint; 



' destitute of spines ; hearing only a few short slender I 

 setae ( 



more or less 

 strongly spini- 

 ferous. J 

 Feet in the ' 

 male and fe 

 male 



■ alike. Internal C well developed 

 lobe of the first-^ 

 pair of maxillse [ rudimentary . 



dissimilar ; right foot of first pair ] 

 in the male prehensile, right of the I 

 second pair very weak and rudi- f 

 l^mentary ) 



Limnicythere. 



Cythere. 

 Eucythefre. 



Cytheridea. 



Lower 



antennae 



5-jointed. 



Upper 



antennae 



short and stout, their united length shorter than that of the pre- 1 

 ceding joint, bearing long curved spines. First two pairs of feet only ( 

 3-jointed. Eight foot of last pair in the male prehensile. Eyesi 

 wanting J 



6- jointed; | 



beset with | short and gi-adually decreasing in length 



simplesetae; J> 



last four I mostly much elongated and slender, imequal .... 

 joints J 



7- jointed; first two joints very large and stout, last five slender and bearing I 

 ^ moderately long setae ............ f 



'5-jointed ; beset with short scattered hairs. Postabdominal lobes broad and short, I 

 bearing three setae. No eyes f 



6-jointed ; 

 last four 

 joints 



'much narrower than the preceding, and bearing scattered short] 

 hairs, which are in part spiniform. Postabdominal lobes rudimen- V 

 tary, destitute of hairs. Two separate eyes . . . . . ) 



not narrower than the preceding, and beset towards the apex with 

 numerous long setae. Postaljdominal lobes larger than ordinary, 

 bipartite, and bearing five setae. One eye ..... 



7-jointed, bearing numerous very long setae, last joint very long and slender ; two 

 basal joints large and stout. I'ostabdominal lobes subconical, directed down- 

 wards, and bearing three hairs. Eyes wanting ....... 



llyohates. 



Xestolehms. 

 Loxoconcha. 



By tliocy there. 

 Gytheroptcron. 



Cytheriira. 



Sclerochilus. 



Pseudocythere. 

 (^Cytherideis) . 



Mouth simple, tubiform ; its orifice surroimded bj^ a circular disk situated at the apex of a large sub-") 

 conical protuberance. Organs of mastication poorly developed and weak. Mandibles styliform ; | 

 palp very narrow, destitute of a branchial appendage. First pair of jaws composed of narrow and yFaradoxostuma. 

 partly imperfect lobes. Upper antennae (>-jomted, very slender; inferior 5-jointed and shorter; fla- j 

 gellum large and robust. Eye single J 



Shell mostly hard and compact, calcareous ; surface generally more or less rough and 

 uneven, occasionally quite smooth. Hinge-margins mostly toothed. Antennee not 

 adapted for swimming, the upper composed of five to seven joints and armed with various 

 setae or spines ; the inferior 4-5-jointed, the last joint the smallest, and armed with one 

 to three curved claws, second joint destitute of the brush of sette which mostly occurs in 

 the Cypridae ; first joint giving origin, at its apex, to a long biarticulate tubular seta, which 

 extends downwards in front of the antenna about as far as the last joint, and above is 

 connected by an efferent tube with a gland situated in the body of the animal. Mandible 

 very similar to that of the Cypridae. One pair of jaws, composed of four segments, with 

 a branchial plate. Three pairs of feet, directed forwards, very much alike in shape, but 

 increasing in length from before backwards ; all of them adapted for creeping, and 

 terminating in a single strong curved claw. The first foot corresponds with the palp of 

 the second maxilla in the Cypridse, the cutting segments being represented by two small 

 setiferous appendages, arising from a common base. Postabdomen rudimentary and 



VOL. XXVI. 3 H 



