RECENT BRITISH OSTRACODA. 



361 





ferous lobe, a subcorneal, simple, or obscurely articulate palp, which projects backward, 

 and terminates in three long setae, and a small branchial plate, bearing six radiating 

 respiratory seta?. Postabdominal rami long and slender, bearing at the apex two long 

 and unequal curved claws, and a short seta; a short seta springs also from the inner 

 margin of the ramus at or below the middle. The males furnished (mostly, if not 

 always) with two mucus-glands, consisting of a cylindrical axis, on which are set seven 

 whorls of radiating filaments, the whole connected with an efferent tube or "vas 



deferens . 

 The males of this genus are, except in a few instances, entirely unknown. Dr. Zenker 





___, indeed, in his excellent memoir on the anatomy of the lower Crustacea, gi> 

 figures and descriptions of the males of three species ; but two of these belong to t he 

 section comprised in the subgenus Cypria of that author, which may ultimately be found 

 to present generic characters distinct from Cypria proper. Fischer has also figured and 

 described the males of some few species. I have myself sought diligently for the male* 

 of many of the commoner species of Cypris, but have only seen one example belonging 

 to C. (Cypria) compressa, Baird. This is one of the species figured by Zenker. Mean- 

 time the peculiarities of the group Cypria seem scarcely sufficient to warrant its separa- 



The "testis," or "mucus-gland," though hitherto seen only 



distinct g 



few species, is doubtless present under some form in the males of all 



And seeing 



-> 



that it is, to all appearance, the secretory gland of the spermatic filaments, or « sperma- 



» there seems no valid reason for applying to it any other name than .hat of 



tozoids 

 testis. 



To this category 



The members of this genus inhabit exclusively fresh or shghtly brackish water and 

 are mostly natatory animals ; but a few of them, which have unusua y shor seU 

 attached to the lower antenna,, seem to he destitute of -"^ ' a »* ^ 

 in fact, a link between VP Hs and C^ona. In external appearance „ «n as m lujtat 

 of life, these approach the latter genus more closely than the W 



belong C. reptans, serratu, and gibba. rwides are not of generic 



Though the structural differences observed »«££ g^ ^ s " cctions 

 importance, they are sufficient to form grounds of separation into 



as follows : 



i ,» „„ fir as or onlr slightly beyond, the apex 

 <■■ Seta: of lower antenna: plumose, subequal, reaelnng abont as far as, or on y g 



of the terminal claws. mod erately long set*. 



* Second foot terminating in a short hooked claw, and one 

 ** Second foot without a claw, ending in three seta;. 



*• Set* of lower antenna: non-plumose, very short, not re* » . 

 * Set. of lower antennte plumose, unequal , two or three exceeding long, 



,. . - * « -x nf wliirh is exceedingly long. 



Second foot 



3d 



VOL. XXVI. 



