376 MR. G. S. BRADY ON NEW OR IMPERFECTLY 



occasionally fringed with hairs ; posterior margin rounded, bearing four or five short 

 processes or tubercles on its inferior portion. Dorsal margin arched, irregularly 

 sinuous, highest at its anterior third. Inferior margin nearly straight, with a slight 

 median convexity. Dorsal aspect compressed, angular, oblong-ovate. End view sub- 

 quadrangular, compressed, about once and a half as long as broad. Surface of the 

 valves marked with several conspicuous ridges, one of which runs longitudinally along 

 the ventral margin, another in a curve parallel with the anterior border, and two or 

 three more in an oblique direction from the ventral ridge towards the dorsum. Between 

 the primary ribs the shell is marked with large subquadrate pits or reticulations. 



Length -^s in. (1'05 mm.). 



Hab. Hunde Islands, 60-70 fathoms {Dr. Sutherland). 



Cythere neptuni (Egger) seems to be the nearest described relative of this fine species. 



12. Cythere clathrata, Reuss. (PI. LIX. fig. 9, a-c ; fig. 10, a-c ; fig. 11, a-d ; 

 fig. 12, a-c; fig. 13, a-c.) 



Cypridina clathrata, Reuss (1849), Haidinger's Abhandl. iii. p. 71, t. 9. fig. 31. 



Cythere lyrata, Reuss, Beitrage zur Charak. der TertiSr-Scliicht. des nordl. u. mittl. Deutschlands, 



p. 62, t. 10. fig. 99. Speyer, Ostrac. der Casseler-Tertiarbild. p. 25, t. 3. f. 4. 

 Cythere latimarginata, Speyer, Ostrac. der Casseler-Tertiarbild. p. 22, t. 3. fig. 3. 



Carapace oblong, subquadrilateral, somewhat ear-shaped, broadest in front. There is 

 a conspicuous rounded tubercle a little in front of the centre of the valve, and two large 

 elongated eminences considerably behind the centre, which coalesce so as to form a 

 much elevated transverse ridge. This ridge is continued forwards more or less dis- 

 tinctly along the ventral margin. The anterior margin of the carapace is obliquely 

 rounded and armed, in the adult, with a series of equal rounded teeth, varying from 

 about fifteen to thirty in number. Posterior margin narrow, rounded, and produced at 

 its inferior angle, where it bears a few (mostly five or six) teeth. Ventral margin 

 straight or slightly convex. Dorsal margin straight, often corrugated, and sloping 

 backwards from the anterior hinge. Dorsal aspect oblong, angularly ovate or subqua- 

 drilateral. Surface (in the adult) marked with closely set and tolerably large pittings or 

 reticulations. 



Length 3*5— aV in. 



Hah. Hunde Islands (vars. nuda, latimarginata, lyrata). Norway (C clathrata, and 

 vars. nuda, laiimarginata) . 



The number of species which I have thought it necessary to include under the 

 specific designation of " clathrata" might, I believe, be fairly increased by the addition 

 of two more species, Cythere hexangulatopora, Speyer, and C. bornemanni, Speyer. The 

 characters upon which these and the previously quoted species rest appear to depend 

 partly upon local variation, but chiefly upon the age of the specimen. I have arrived 

 at this conclusion from the careful examination of a large number of specimens of all 



