212 



POST-TERTIARY ENTOMOSTRACA. 



ScLEROCHiLUS coNTORTus {Normm). Plate X, figs. 33 — 35. 



1862. Cythere contorta, Norman. Ann. Mag. N. H., vol. ix, p. 48, pi. ii, fig. 15 



Trans. Tyneside Nat. F. C, vol. v, p. 150, 

 pi. iii, fig. 15. 



1865. ScHLEEOCHiLUS CONTORTUS, Sars. Overs. Norg. mar. Ostrac, p. 90. 



1868. — — Brady. Monog. Rec. Brit. Ostrac, p. 455, pi. 



xxxiv, figs. 5 — 10 ; pi. xli, fig. 7. 



Shell of the female, as seen from the side, elongated, bean-shaped, higher behind 

 than in front, greatest height less than one half of the length, situated behind the middle. 

 Extremities well rounded ; superior boldly arched ; inferior deeply sinuated in front of 

 the middle. Seen from above, compressed, ovate, extremities acutely pointed, width 

 scarcely equal to one third of the length. End-view ovate, rounded above, pointed 

 below. Surface perfectly smooth. Colour yellowish. 

 Length, yjth of an inch. 



Distribution. Hecent. — Britain, Norway, Bay of Biscay, Spitzbergen. 



Fossil. — Scotland : in nearly all the Post-tertiary beds. South Wales : Cardiff New 

 Dock-basin. Ireland : Belfast New Dock, Portrush. Norway and Canada. 



Gems 14 — Paradoxostoma, Fischer. 



Shell thin and fragile, smooth, shining, and having no definite structure ; valves sub- 

 equal, mostly much higher behind than in front, usually elongate-ovate. Lucid spots as. 

 in the preceding genus. Hinge-joint simple. Ventral margins emarginate in front, so 

 that when the valves are closed there is still an elongated orifice through which the 

 suctorial mouth can be protruded. Upper antennae exceedingly slender, 6-jointed, and 

 bearing short setae; lower shorter and more robust, 5 -join ted; flagellum large and 

 almost as thick as the antenna itself. Poison-glands large and mostly lobulated. 

 Mouth suctorial. Labrum and labium forming together a large and stout subconical 

 process projecting downwards, and terminating in a disk with elevated margins, in the 

 middle of which the orifice of the mouth is situated. Mandibles very slender, protractile, 

 styliform, subulate at the apex; palp very slender and elongated, indistinctly jointed 



