CYTHERE. 161 



Distribution, decent. — Great Britain, Ireland, Norway, Gulf of St. Lawrence, 

 Spitzbergen, Davis's Straits. 



Fossil. — England : Bridlington. Scotland : in nearly all the Post-tertiary beds. 

 Ireland : Woodburn, and New Docks, Belfast. Canada and Norway. Post-tertiary beds. 



27. Cythere emaciata, Brady. Plate IX, figs. 14 — 17. 



1866. Cythere emaciata, Brady. Brit. Assoc. Report, p. 210. 

 1868. — — Brady. Monog. Rec. Brit. Ostrac, p. 414, pi. xxxi, 



figs. 31—37. 



Carapace (of the male?), as seen from the side, oblong, subquadrangular, greatest 

 height situated in front and not equalling half the length. Anterior extremity forming 

 a somewhat flattened curve and faintly toothed below; posterior rather narrower, 

 obliquely concave above the middle and produced below into four or five short blunt 

 teeth ; superior margin sloping backwards almost in a straight line ; inferior very slightly 

 sinuated. Outline, as seen from above, compressed ovate, nearly thrice as long as 

 broad ; sides nearly parallel ; anterior extremity obtuse and centrally emarginate ; 

 posterior broadly emarginate in the middle and produced on each side into a more or 

 less conspicuous spinous lobe. Surface of the valves marked with two or three 

 prominent longitudinal ribs, which towards the anterior extremity anastomose, forming a 

 network of large polygonal areolse ; the remainder of the shell is covered with large and 

 deep subcircular excavations, which are arranged chiefly in longitudinal rows. The 

 dorsal aspect shows a deep sulcus in the line of the hinge-margins, and the contact- 

 margins on the ventral surface are considerably introverted and bordered by a wide 

 smooth band. 



Length, -^rd of an inch. 



Cythere emaciata occurs in the living state in depths of ten to thirty fathoms on the 

 southern shore of England, and the west of Ireland and Scotland; the Scottish 

 specimens, however, being few and stunted in growth. 



Distribution. Becent. — Great Britain and Ireland. 



Fossil. — Raised beaches, Oban and Portrush. 



28. Cythere quadridentata, Baird^ Plate XIII, fig. 22. 



1850. Cythere auADRiDENXATA, Baird. Brit. Entom., p. 173, pi. xxi, fig. 2. 

 1868. — — Brady. Monog. Rec. Brit. Ostrac, p. 413, pi. xxxi, 



figs. 19—30. 



21 



