RECENT BRITISH OSTRACODA. 



397 



3. Cythere viridis, Miiller. (Plate XXVIII. figs. 40, 41, & 57-59; and Plate XXXVIII. 

 fig. 8.) 



Cythere viridis, Miiller, Entomostraca, p. 64, tab. vii. figs. 1, 2 ; Sars, Oversigt af Norges marine Ostrac. 

 p. 30. 



Britisli type. Distribution : Recent — Norway, Great Britain, and Ireland. Fossil — Raised beaches 

 and glacial clays, Norway, Scotland, and Ireland. 



Very similar to the foregoing, but much smaller. Shell of the female, as seen from 

 the side, subreniform, slightly higher in front than behind, greatest height equal to two- 

 thirds of the length. Anterior extremity obliquely rounded ; posterior rather narrower, 

 rounded. Dorsal margin nearly straight, sloping gently backwards from the front, where 

 it is slightly angular ; inferior distinctly sinuated in front of the middle. Seen from 

 above, the outline is ovate, more sharply pointed in front than behind, about twice as long 

 as broad. Surface marked with numerous fine puncta, which are interspersed with small 

 tubercles. Colour olive or yellowish-brown. The shell of the male is much narrower 

 and more elongated. The animal itself is almost colourless. Last joint of the upper 

 antenna much elongated, almost equal in length to the two preceding. Eeet very short. 

 " Copulative organs of the male subtriangular, the apical portion obtusely rounded." 



Length in., height ^ in. 



Hub. The Minch, 45-60 fath. {Mr. J. G. Jeffreys) ; Shetland, Peterhead, Isle of Man, and Cumbrae {Mr. 

 D. Robertson) ; Galway Bay, Birterbuy Bay, Baltimore, Roundstone Bay, Stranraer, and in tide- 

 pools near Sunderland {G. S. B.) ; in tide-pools, Arran and Channel Islands {Rev. A. M. Norman) ; 

 Girdler sand, Thames, and Scarpa Flow, Orkney {Mr. E. C. Davison). 



C. viridis might very easily be passed over as the young of C. lutea ; but, besides that 

 the shell-characters are very constant, those of the animal itself are quite sufficiently 

 distinct. It is not by any means so common a species on the northern British shores ; 

 but it may often have escaped notice on account of its small size. 



3. Cythere pellucida, Baird. (Plate XXVIII. figs. 22-26, 28.) 



Cythere pellucida, Baird, Brit. Entom. p. 173, t. xxi. fig. 7 ; Sars, Oversigt af Norges marine Ostrac. p. 31. 



British type. Distribution : Recent — Norway, Great Britain and Ireland, Mediterranean. Fossil — 

 Raised beaches and glacial clays, Norway, England, Scotland, and Ireland. 



Valves of the female compressed, oblong ; as seen from the side, subquadrangular, equal 

 in height throughout, rounded in front, angulated behind on the dorsal margin, height 

 equal to less than half the length. Anterior margin obliquely rounded, posterior sub- 

 truncated rounded off below, almost rectangular above. Dorsal margin very slightly 

 arched, ventral distinctly sinuated in front of the middle. Outline, as seen from above, 

 compressed ovate, greatest width near the posterior extremity and equal to one-third 

 of the length. End view broadly ovate. The male is much more elongated than the 

 female, and has the supero-posteal angle more produced. The centre of each valve is 

 marked with a distinct transverse sulcus, and sometimes also with two shallower ones 

 near the extremities. The substance of the shell is rather thin and horny ; its surface 

 covered with thickly set, circular or often oblong puncta, which vary much in size in 



