RECENT BRITISH OSTRaCODA. 



Ai: 



) 



a pitted surface, often without papillae (both rules, however, being liable to occasional 

 exceptions) : in C. punctillata we see a mixture of these two character. 



Bairdia hebertiana, Bosquet, and B. punctatella, Bosquet, are both nearly allied to 

 the present species, but not absolutely identical with it. M. Bosquet, to whom I have 

 | submitted specimens, agrees with me in this determination. Reuss's Cytherina niter- 

 media comes, perhaps, still nearer; but his figures are insufficient for the purpose of 

 identification. Cytheridea Mulleri, Bosquet, is also a very near relative, but is separated 

 by the constant tendency to dentation of the anterior, and sometimes of the posterior 

 margin; this character is entirely absent in C. punctillata. 



The only British locality in which this species has been found abundantly is Loch 

 Fyne, where, as previously stated, it occurs in great numbers in company with C. papulosa. 

 It is by far the most abundant species in the Scotch glacial clays. 



t. Cytheridea torosa (Jones). (Plate XXVIII. figs. 7-12, and Plate X X X I X . tig. :>.) 



Vandona torosa, Jones, Ann. & Mag. Nat. Hist. ser. 2, 1850, vi. p. 27, pi. 3. fig. f>. 

 Cijprideis torosa, Jones (in part), Tertiary Entom. of England, 1866, p. 21; Brady, Ann. & Mag. Nit 

 Hist. vol. xiii. (1864) p. 62, pi. if. tigs. 11-23, and Trans. Tyncside Nat. Field Club, vol. vi. p. 108, 



1 • • • /"> ■» w ^-^ ,-«w s-*+ ^-v r^* 1 • / w 1 



pi. hi. figs. 11-23 ; G. O. Sars, be. cit. p. 51. 

 British type. Distribution : Recent— Norway, Great Britain, Ireland, Levant, Sea oi Azofl. 



til— 



Posttertiary, England and Scotland. 



Shell of the female, as seen from the side, oblon 



- 



cely equal 



the height. Dorsal margin arched, highest in front of the middle, where it i^ 

 slightly gibbous. Ventral margin straight, or slightly incurved at the anterior third, 

 mostly furnished with a single stout spine at the posterior angle. Extremities well 

 rounded. The outline, as seen from above, is oblong-ovate (often irregularly and obso- 

 letelv angular), sides nearlv parallel, extremities obtusely pointed; the line of junction 

 of the hinge-margins depressed behind the middle, forming a longitudinal sulcus Imd 

 view very broadly oval, nearly circular. The right valve is smaller than the left, and 

 bas the dorsal margin inclined more steeply, and almost in a right line, from before 

 backwards. Shell of the mate elongated, more 



Surface of 



valves marked with closely set rounded pitting* and with a more or less vwpKOCW „, ins 

 verse suleus somewhat in front of the eentre. Young specimens are sometime furmshed 



— - »„ short, thinly scattered hairs, and at the postero-mfer-or angle 

 before mentioned, there is often a conspicuous group of rather long hairs 



ith a fe 



I Aicid 



°»uc ueiore mentioned, meru is uulu « *~ — r — - ,-^w^ OTU i 



c u« rt * four. Tipir the sulcus, with two isolated and 

 spots arranged in a transverse row of about foui near tne suit , 



widely separated spots considerably in f^^^Z J e ' (in 12). 

 ment does not differ materially from that of the ttio P receain f * , 



Colour dull brown. Eves distinct. The penultimate jomt of «-££«' "*» 



ly longer than the preceding; the last tfj^g^ anUnum v ,. rv long 

 three set*; spines long and slender. Tennmal ws f 1 ow > 



Branchial appendage of the "^^ ^^IU^ °^ « "" 



Ust three joints of the first foot about equal » len » t I 



joint of the last foot much longer than the following two, and g 1 



Joint of the last foot much 



vol. XXVI. 





