68 EOCENE MOLLUSCA. 



9. Modiola Mitchelli, Morris. Tab. XIII, fig. 10. 



Modiola Mitchelli. Morris. Geol. Journ., vol. x, pt. 1, p. 158, t. 2, figs. 12, 13, 1854. 

 — — Id. Catal. Brit. Foss., p. 211, 1854. 



Spec. Char. "31. testa tenia, lavi, subtrigond, antice obtusd, postice dilatatd ; cardine 

 marginuli recto." 



" A somewhat trigonal, depressed, and dilated shell, with the umbones obtuse, the 

 dorsal line straight, the byssal margin nearly straight or but very slightly curved, the 

 surface nearly smooth or faintly marked by lines of growth." {Morris.) 



Length, 1 inch. 



Localities. New Cross, Deptford, Lee and Blackheath {Morris). 



"This species is near to Dreissena antiqua, Melt., but the dorsal margin is more pro- 

 duced, and the general character of the shell more spatulate." 



"Not rare in the upper part of the AYoolwich series, but it is rarely found perfect.' 

 Mr. Prestwich's cabinet. 



10. Modiola nodulieeua, S. Wood. Tab. XIII, fig. 8, a, b. 



Spec. Char. 31. testa tenui, irrcgulariter trapeziformi, valde inequilateral) ; pedi- 

 regione parvd, margine subrotundald, siphoni-regione magna, dilatatd ; extus radial in/ 

 striata, striis magnis, biftircatis, nodidiferis ; margine ventrali ineurvd. 



Shell thin, irregularly trapeziform, very inequilateral ; the pedal region small and 

 rounded, siphonal region expanded, covered with large, birfurcating, and nodulous radia- 

 tions; ventral margin somewhat curved. 



Length, -| an inch. 



Localitg. Barton {Edwards). 



One specimen is all that I have seen, but its ornamentation is so different from 

 that of any other species that I think it must be distinct. The striae which cover the 

 entire surface are peculiar in bifurcating at a very early period. Near the umbo they do 

 not amount to more than half a dozen, while at the outer margin of the siphonal region 

 as many as thirty-five may be counted; these stria?, are rather broader than the interme- 

 diate spaces, and they are ornamented with a small knob or thickening at regular 

 distances. 



11. Modiola Nystii, Kichx, MSS., sec. Nyst. Tab. XII, fig. 8, a, b. 



MrriLUS Nystii. Nyst. Coq. Foss. Belg., p. 2/0, pi. 20, fig. 8 b. 



— — Id. Rech. Coq. Foss. de Hoesselt et Kl. Span., p. 14, No. 35, pi. 3, 



fig. 35, fide Nyst. 



— iiastatus. Gold/. Petr. Germ., p 179, pi. 131, fig. 13. 



