RECENT BRITISH OSTRACODA. 



$09 



As Fischer lias identified Miiller's C. strigata with a species which seems to he very 

 different from the present, I have thought it best to describe our British species under a 

 new name. 



** Second foot without a claw, terminating in three moderately long and nearly equal seta. 



12. CrpRis gibba, Eamdohr. (Plate XXIV. figs. 47-54, and Plate XXXVI. % 2.) 



Cypris gibba, Ramdohr, Magaz. d. Gesellsch. naturforsch. Freunde zu Berlin, 1808, ii. p. 1)1, t iii. 

 figs, 13-17 {fide Jones) ; Jones, Tertiary Entom. p. 15, pi. i. figs. 3fl-/ ; and woodcut, fig. 1, p. 16. 



Valves oblong, oval, nearly equal in height throughout, marked generally, but not 

 always, by two deep transverse snlci extending from the anterior half of the dorsum to 

 the middle of the valve. Extremities well ronnded and nearly equal, fringed with hairs. 



< 



Dorsal margin straight; ventral deeply sinuate in the middle. Seen from above, 11 

 carapace is oblong-ovate, narrowed in front and rounded behind, marked on the anterior 

 half by one or more deep transverse sulci. End view subquadrate, keeled. Surface of 

 the shell deeply and coarsely punctate (fig. 51), cream-coloured or light brown, sometimes 



nearly white. The shell is much thicker and stronger than that of any other Cyprit 

 with which I am acquainted. The second foot bears at the apex of the terminal joint 

 three long setee, two of which are nearly equal in length, the other considerably short r : 

 the penultimate joint has also two long and equal setse springing from its inner margin ; 

 and another, somewhat shorter, rises from the apex of the second joint. Post abdominal 



flexuous, ending in two long and equal claws, and one very short seta ; the marginn 



O iXX """ ^~£> 



sually long, and is attached somewhat below the middle of the ramus 



very black and conspicuous 

 Length A- in. . height -^ in. 



CyprkgMa seems to be an almost ubiquitous species, but is liable to escape obser- 

 vation, owing to its babit of creeping on tbe bottom or imbedding itself in the mud or 

 soft clay. It is nevertheless a true %m. the lower antenna, bearing a tuft of bug 

 set*, and tbe second pair of jaws a branchial appendage. The armature of he second 

 pair of feet is peculiar, and the shell-structure very different from that -»*?-« » 

 tbis genus. The markings of the surface are very variable some specimens b g a , 

 gether devoid of grooving or tuberculatum, while others arc deeply urn-, a- or t sulca 

 These variations do not seem to depend entirely upon age, bough m joung spu ,men 



the sulci and tubercles are. as a general rule, feebly developed or absent. 



h' to the apex of the terminal r fairs. 



b Seta of lower antenna scarcely plumose, very short, not reaching 



13. Cypris trigonella, n. sp. (Hate XXV. figs. 41-tl.) 



Valves elongated, snbtr iallar, highest in the middle; heght equal to mmc ft. 



11 ' postica nempe lunata, media obliqua, antica 

 aperturam sublinearis ; ratals convexiuscute, fuse*, faseiis tnbus albi* p »«* ^^ ^^ ^.^ ^^ „ 

 arcuata ; y e l, si mavis, valvul* albae, margine dorsali cingulo fusco erne m, ^^ 



