CYTHERE. 171 



40. Cythere Jonesii [Baird). Plate XII, figs. 4 — 7. 



1850. Cythekeis Jonesii, Baird. Brit. Entom., p. 175, pi. xx, fig, 1 ; Norman 



(1865), Nat. Hist. Traus. Northumberland 

 and Durham, vol. i, p. 21, pi. vii, figs. 5 — 8. 

 1852. Cytheke cekatopteba. Bosquet. Entom. foss. terr. tert. France, p. 114, 



pi. vi, fig. 2; Jones (1856), Monog. 

 Tert. Entom., p. 39, pi. iv, fig. 1. 

 1856, ? Ctthereis cobnuta (young), Jones. Monog. Tert. Entom., p. 39, pi. iv, 



fig. 19. 

 1862. — FiMBEiATA, Norman. Ann. Mag. N. H., ser. ill, vol. ix, pi. iii, 



fig. 9. 

 1865. — sPECTABiLis, Sars. Overs. Norg. mar. Ostrac., p. 46. 



1865. — suBCOBONATA, Brady. Trans. Zool. Soc, vol. v, p. 384, pi. k, 



figs. 9 a—e, and (?) Speyer (1863), 

 Ostrac. Casseler Tertiarbild., p. 38, 

 pi. iv, figs. 9, 10. 

 1868. Cythebe Jonesii, .Brac^y. Monog. Eec. Brit. Ostrac, p. 418, pi. xxx, figs. 



13—16. 



Carapace, as seen from the side, ear-shaped or subquadrangular, higher in front than 

 behind, greatest height considerably more than half the length ; anterior margin rounded, 

 fringed with blunt spines below the middle ; posterior subtruncate, armed with a series 

 of strong spines which are largest towards the ventral angle ; inferior margin gently 

 convex ; superior much shorter than the inferior, sloping gently from before backwards, 

 its anterior extremity forming a conspicuous angular elevation: Outline, as seen from 

 below, irregularly lozenge-shaped or subrhomboidal, bordered with strong spinous 

 projections, which gradually increase in size from the front to the posterior third, where 

 they terminate abruptly ; greatest width equal to two thirds of the length, situated behind 

 the middle. End-view triangular, equilateral ; the base perfectly straight. The surface 

 of the shell is quite smooth and rises gradually from the front to near the posterior 

 extremity of the valves, there forming an abrupt spinous declivity. A strongly developed 

 ridge commences at the anterior hinge or " eye-tubercle," running a little withm and 

 parallel to the anterior and inferior margins, as far as the transverse declivity just 

 described ; this ridge is in the first portion of its course smooth and rounded, but near 

 the middle of the anterior margin becomes spinous and retains that character to the end, 

 the spines of which it is composed being about ten in number, very large and strong, 

 rounded at the tips ; a little below and behind the middle of the superior margin 

 is a shorter row of similar strong processes, three or four in number and arranged 

 longitudinally. 



Length, ^sth of an inch. 



