CYTHERE. 



149 



10. Cythere albomaculata, Baird. Plate IX, figs 1 — 4. 



1850. Cythere albomaculata, Baird. Brit. Entom., p. 169, pi. xx, fig. 7. 

 1868. — — Brady. Monog. Rec. Brit. Ostrac, p. 402, pi. xxviii, 



figs. 33 — 39, and pi. xxxix, tig. 3. 



Carapace, as seen from the side, subreniform, greatest height in the middle and equal 

 to half the length. Anterior extremity obliquely rounded, posterior rounded, angular 

 in the middle, above which it is often slightly emarginate ; superior margin gently and 

 evenly arched, almost straight in the middle ; inferior deeply sinuated in front of the 

 middle. Outline, as seen from above, oblong-ovate, Avidest in the middle, and nearly 

 thrice as long as broad ; extremities pointed ; surface of the shell smooth, bearing a 

 few short distantly scattered hairs and often some faintly impressed punctse : the 

 extremities marked with numerous radiating, hair-like lines. 

 Length of an inch. 



This is one of the commonest of living British species, occurring abundantly both 

 between tide-marks and in moderate depths of water. It is not recorded by G. 0. Sars 

 • as a Norwegian species, but we have seen a single specimen dredged off that coast. 



Distribution. Recent. — Great Britain, Ireland, Norway, Levant, Cape Verd. 



Fossil. — Scotland : Cumbrae, West Tarbert, Dipple, Raised beaches, Oban and 

 Cumbrae. Ireland : Belfast New Docks, Portrush. 



II. Cythere leioderma, Norman. Plate IX, figs. 5, 6. 



1868. Cythere leioderma, Norman. Last Shetland Dredging Report, p. 291. 

 1870. — — Brad]). Ann. and Mag. N. H., 4th ser., vol. vi, p. 451, 



plate xix, figs. 1 1 — 13. 



Carapace, as seen from the side, oblong, sub-quadrangular, highest in front of the 

 middle, greatest height equal to nearly half the length. Anterior extremity rounded, pos- 

 terior obliquely subtruncate, sinuated in the middle ; superior margin highest in front of 

 the middle, where it forms an elevated angle from which it slopes gently backwards almost 

 in a straight line ; inferior margin almost straight. Seen from above tumid, ovate, slightly 

 narrowed in front ; greatest width equal to the height and situated near the middle ; 

 extremities broadly and evenly rounded ; hinge-margins somewhat depressed ; hinge-teeth 

 very strongly developed. Surface smooth, bearing numerous short scattered setse, and 

 marked on the anterior margin with several radiating lines. 

 Length, ^^Sh of an inch. 



We have met with only one fossil valve of this species, but the characters are so well 



