RECENT BRITISH OSTRACODA. 



465 



I have not succeeded in detecting the sexual organs of the two species belonging to 

 this genus; but it seems pretty certain that the forms referred to in the generic dr- 

 scription are really the two sexes of one and the same species. The shells of the two 

 forms present no appreciable difference; and the several pairs of jaws, the mandibular 

 and "oviferous " feet, and the postabdominal laminae are in both precisely alike. 



• 



1. Cylindroleberis Marine (Baird). (Plate XXXIII. figs. 18-22, and Plate XLL 



fig. 1.) 



Cypridina Maria, Baird, Proceedings Zool. Soc. Lond. part xviii. (1850) p. 257, pt mi. (Aimulota) 

 figs. 5-7. 



Carapace, as seen from the side, oblong-elliptical, more than twice as long as high 

 rather higher in front than behind. Dorsal and ventral margins nearly straight, sub- 

 parallel; beak erect; notch wide, almost rectangular. Extremities obtusely roundel, 

 the posterior rather narrowed. Outline, as seen from above, oblong, subclayate, about 

 twice as long as broad, greatest width in front of the middle; extremities rounded, the 

 anterior deeply cleft in the centre. Notch radiated, produced along the median lines of 

 the dorsal and ventral aspects as well as laterally. End view nearly circular. \1 iisok 

 spots very numerous, forming a conspicuous patch near the centre of the valv< 

 pellucid, and showing through it the deep-yell owish-br own body of the animal ; » row, ng 

 altogether opaque with age. Eyes black and plainly visible through the shell rather 

 behind and above the centre. Upper antenna of the male altogether more slender and 

 less densely setose than in the female; auditory seta short and stout, dilated and 

 obliquely truncate at the apex; terminal claw also short and stout scarcely half the 



i a j • • i- ^ffV.P Tintitorv branch of the lower ant enna 



length of the adjacent set*. Second joint of the natatoiy bran 



Shell 



female short 



ly longer than the following joints ; in the maU nearly 



as the first joint. First pair of maxilla, subquadrate, bearing ^^Z S 

 dage. Ovif rous foot terminating in two equal numerously dentate bp ; s 

 rather irregularly spined toward the apiee, Postabdommal lamm* Wl ba an 

 gular, obliquely truncate behind, armed with six slender manually dentate, h htl 

 eurved elaws. which decrease regularly in length from below upwards. 



Length A- in. 



&""• 11 



Baird); Shetland, Penzance, and with me p*~~ 

 Norman) ; taken in the towing-net at Cumbrae [M; 



nerm { «ev. a. m. «arman, ; «— - Fhilome des longicomis, is a much 



C. Mori; though mostly taken m "W^**^ very manv. 

 scarcer species, the specimens taken at any one time being ne^ ry ; 



s /-Di *« VXXIII figs. 6-9, and Plate X LI. fig. 2.) 



2. Cylindroleberis teees (Norman). (Plate XXXlli. n D 



,1. viii. (Oct. 1861) pi. xiv. fig. 10. 



irle ovate highest behind the middle; 

 Carapace of the female, as seen trom me sine, ^^ extremities rounded, 



greatest height equal to more than two-thirds o ^J ^ a l y convex; notch 



anterior narrowed, posterior broad ; superior an middle, more 



very narrow, curved. Outline, as seen from above, ovate, Will* ^ ^ 



Norman. Ann. & M 



from tl 



VOL. XXVI. 



