RECENT BRITISH OSTRACODA. 



427 



have already gained a certain currency, it seems best not to disturb the exist in 



for the sake of adherence to a law which, in this case, would further contuse 



matters. 



5. Cytheridea laousteis (G. 0. Sars). (Plate XXVI. figs. 18-21, and Plate XL. ng. 2.) 



Cy there lacustris, G. O. Sars, Zoologisk Reise i Sommeren 1862, p. 30. 



Cyprideis torosa, Jones (in part) , Tertiary Entomostraca, p. 21, pi. ii. figt. la-It, and woodcut, p. 16. fig. 2 



Distribution : Recent— Norway, Scotland. Fossil— Posttcrtiary, England. 



Valves of the female', as seen from the side oblong, subtriangular, highest in front ; 

 greatest height equal to more than half the length. Anterior margin broad and well 

 rounded; posterior narrowed, obscurely angular above, rounded off below. Superior 

 margin much elevated and angular over the anterior hinge, thence doping steeply back- 

 wards in a right line; inferior straight or very slightly sinuated in front of the middle. 

 Outline, as seen from above, oblong oval, irregularly emarginate; sides nearly parallel ; 



deep Ion 



•I'll. 



extremities equal and obtusely pointed; width equal to half the 

 dinal sulcus formed by the depression of the hinge-margins behind the middle 

 ventral surface is marked with faint, jagged, longitudinal furrows. End view ova ,, 

 broad below, pointed above. The shell is thick and dense m structure, cov,r,,l w, , 

 closely set ir^gZ fittings, and with scattered papilke, each of wh.ch seem be 01 

 posed of four small points arranged in a rosulate manner ; often these a lu. d o . t 

 form one papilla wfth a central perforation. Valves transversely subeate and b 

 several irregularly placed rounded tubercles. Colour pale yellow isl no»n . Itage , , 

 that of effii except that the terminal — jJ^J^LTSSlS 



crenated. Limbs very robust. Jp- £fZ^ £* M are about equal in 



considerably longer than erther of the ^™ *«" t J the foll(min „ two; s.-in.-s 



length and very short; the antepenultimate about equal 



.„„! -.. -,~ aL TTw^ti™ seta of the lower antenna very short, tenoning 



_ and slender. TJrticatin 



of the terminal claws 



th to tl 



as * ... « .•* - -ji** ■- z: 



rery stout Ilex 



^ „ „ three following Joints, bearing cm it. £^~f^ al ' xt _ ity; last 



seta; second joint narrow at the base and m ^ ^ ^^ ^^ ^^ 



two joints very short, and distinctly sepaiateci, ^ ^ ^ ^ much 



and equal in length to the three preceding joint ^ r ^ ^ ^^ >t 

 l^™„ +i,_ + i_ wi^nff two. which, like tnose ui 



go* than the following to 

 the apex. Male unknown 



Length ^ in., height * m. ^ ^ Canal (M ,, D . /MerftM ,. 



Hab. North Rliaws Tionli. Selkirkshire (Or. a. *>•) > » a«iW«Va1»nw in ' 



6. North Shaws Loch, Selkirkshire v u. a. *>•> , • lkirk>hire in 18* 



«f tiik verv interesting species m « 

 I took one imperfect specimen of tins veiv abundant ly in the neighbourhood 



hich time ^M» g* c ; vs of Hornsea, Yorkshire ; and at Grays 



Glasgow. It occurs fossil 



r> 



Essex 



3 m 2 



