418 



MR. G. S. BRADY'S MONOGRAPH OF 



The Frith of Clyde seems to be peculiarly rich in the spinous forms hitherto referred 

 to the genus Cythereis, Mr. Robertson having there dredged all the British species in a 

 living state: Cy there antiquctta appears to be the commonest and most widely distri- 

 buted of these, but is nowhere very abundant. It is not mentioned by Sars among the 

 Norwegian Ostracoda. 



32. Cytiibeb Jonbsii (Baird). (Plate XXX. figs. 13-16.) 



Norman, Nat. Hist. Trans. Northumber 



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

 •fimbriata, Norman, Ann. & Mag. Nat. Hist. Ja 



Caj there ceratoptera, Bosquet, Entom. fossil, des terr. tertiair. de la France, p. 114, pi. vi. fig. 2; Jones, 



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

 Cythereis spectabilis, Sars, loc. cit. p. 46. 



subcoronata, Brady, Trans. Zool. Soc. vol. v. p. 384, pi. lx. figs. 9«-e, and (?) Speyer, Ostrac. der 



Casseler Tevtiarbild. p. 38, tab. iv. figs. 9, 10. 

 'f i /thereis cornuta, Jones (young), Entom. of Tert. Form. Eng. p. 39, pi. iv. fig. 19. 



Atlantic type. Distribution: Recent — Norway, Great Britain ; (var. ceratoptera) Ireland; Bay of Biscay, 



Levant. Fossil — Glacial, Scotland j (var. ceratoptera) tertiary, France, Belgium, England. 



Valves compressed in front, but gradually swelling towards the hinder extremity ; as 

 seen from the side, oblong, subquadrangular or ear-shaped ; height equal to much more 

 than half the length. Anterior margin rounded, spinous below, and terminating above 

 in a well-marked angular elevation over the anterior hinge. Posterior extremity irre- 

 gularly bordered with spines, the strongest of which are at the ventral angle. Ventral 

 margin gently curved; dorsal much shorter than the ventral, straight but emargi- 

 nate, and forming an elevated ridge, which bears at its posterior extremity three or 

 four strong, linguiform processes. The outline, as seen from below, is irregularly lozenge- 

 shaped or subrhomboidal, and bordered with strong spinous projections, which gradually 

 increase in size from the front to the posterior third, where they terminate abruptly ; 

 width equal to two-thirds of the length. End view equilaterally triangular, 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 valve, at which point the elevation 

 terminates abruptly in a jagged and spinous declivity. A strongly developed ridge com- 

 mences at the anterior hinge-tubercle, running a little within and parallel to the anterior 

 and ventral margins, as far as the transverse declivity just described; this ridge is, in 

 the first portion of its course, smooth and rounded, but at the antero-ventral angle 

 becomes spinous, and retains that character to its termination : the spines, or " lingui- 

 form processes," are about ten in number, very large and strong, with rounded ex- 

 tremities. Colour ochreous. Eye-tubercles very large and prominent. Antennse elon- 

 gate, almost exactly similar to those of C. chmelmensis. Eeet slender ; second joint of the 

 last pair shorter than the united lengths of the following two. Apical portion of the 

 male copulative organs forming an elongated acuminate process. 



Length ^ in., height & in. 



