RECENT BRITISH OSTRACODA 



t73 



first two joints larger than the rest, and forming between them a distinct (Bfeniculation ; 

 lower antennae composed of a large, broad, biarticulate, and geniculate basal portion, from 

 which arise two flattened unequal branches, one Particulate, the other triartirulate, botli 

 beset with very numerous long setae. Labrum large, subglobose, giving out in front a 

 short subtriansfular process. Mandibles very weak, strongly inttcxed at the lower 



emity, which is obliquely truncate and set in a pectinate manner with shnd 

 palp large and elongate, almost straight, bearing on the inner side very numerous Ion 

 pectinately arranged setae, which stretch backwards as in the feet of the SidiuV. First 

 pair of jaws bearing at the base a very large branchial plate, which is beset with numerous 

 ciliated marginal setse ; incisive portion divided into three setiferous lobes; palp very 

 large, scarcely articulated; the posterior margin slightly lobated; the inner margin 

 pectinately setose, like the mandibular palp, but smaller. Second pair of jaws membra- 

 naceous, bearing, like the preceding pair, a branchial plate, but smaller and narrow. t; 

 distal portion subovate, beset with a few ciliated setae, and in the male furnished 

 very large and strong hatchet-shaped appendage adapted for prehen * 



the female, rudimentary, forming a simple setiferous lob 



Third c 



distinctly jointed and subcheliform. Abdomen beset behind with several bundles ol Ion, 

 setse for supporting the ova. Postabdominal laminae narrow, slightly dilated at 1 ho apex, 

 and armed before and behind with several marginal set* or spines. Copulative organs 



of the male verv large and narrow." 



From this definition of the genus it will he seen that it differs very remarkably from 

 all hitherto known forms, presenting, in the conformation of the lower antenna, a remark- 

 able approach to the Copepoda, and in the palps of the mandibles and first pair ol jn 

 a likeness to the Siditte. The way in which the animal uses its powerful limbs >s not 

 known, it never havinar been observed in the living state. 







1. Cytherella scotica, Brady. (Plate XXXIV. figs. 18-21.) 



Cytherella Scotica, Brady, Brit. Assoc. Report, 1866, p. 211. 



Valves, as seen from the side, rather obliimely subelliptical, *£*«££* 

 throughout ; greatest height eoual to more than half »£g£^£!EL 

 posterior obliquely rounded, superior and interior J"^ - ** int( , (1 mi slightly 

 Outline, as seen from above, subcorneal, snbtruncate^ bel .M ebtu -P to 



in front ; greatest width f-*-"* £j S converging V b 



-tuer less than half the length, lateral margins neaii} si * ^ ^^ ^ 



towards the front ; hinge-line slightly flexuous near the to ^ 



the shell smooth, faintly punctate, more especially to* aid* 1 



emarginate in front 



Surface of 



Colour whitish, opaque. Animal unknown 

 Length ^ in. 



Hab. The Minch (Mr. Jeff) 



pecies have occurred to the R 



Two or three specimens only of this *£^Jg^ coast by Mr. Jeffreys 



A~ M. Norman and myself, amongst sand oreu^ ^ ^^ x ^ specimen . 



It is very nearly allied to Cytherella abyssonm, fears , an , > ^ 



VOL. XXVI. 



