64 EOCENE MOLLUSCA. 



2. Modiola Deshayesii, /. Sowerby. Tab. XIII, fig. 14, a, h. 



Lithodomus Deshayesii. J. Sow. in Dixon's Geol. of Sussex, pp. 94, 171. t. 2, fig. 28. 



— — Morris. Catal. Brit. Foss., p. 207, 1854. 



Modiola lithophaga. Desk. Coq. Foss. des Env. de Par., t. i. p. 267, t. 38, figs. 10 — 12. 



— — Pictet. Traite de Palaeont., vol. iii, p. 584, pi. 81, fig. 9. 

 Mytilus lithophagus. Desk. Trait. Element, t. 37, figs. 5, 6. 

 Lythodomus sublithophagus. IfOrb. Prod. Palaeont., p. 391, No. 1083. 



— — Bellardi. Catal. Ragion. dei. foss. Numm. d'Egitto, p. 26, 



No. 62, 1854. 

 Modiola Deshayesii. Desk. An. sans Vert, du Bassin de Par., t. ii, p. 18, 1860. 



Spec. Char. M." testa elongatd cglindraced, recta ; antice tumidiore ; extremitatibus 

 obtusis ; striis longitudinalibus postice brevibus ; striis transversis irregular ibus, decussalis." 



Length, 1 inch. 



Localities. Bracklesham {Dixon). 



France, Parnes, Chaumont {Desk.), Egypt, Sindc {Bellardi). 



The figure above referred to is a copy of the one in Mr. Dixon's work. The specimen 

 cannot now be found. 



The Paris basin shell, when first described, was doubtfully considered to be a variety 

 of the existing species, under which name it was then published. M. Deshayes, in his 

 'Hist, des An. sans Vert, du Bassin de Paris,' p. 18, has adopted, the above specific 

 one, which was given to it by Mr. Jas. Sowerby, who considered it sufficiently different to 

 be entitled to a distinct position, and M. Deshayes is now of the same opinion. I regret 

 not having been able to see the British fossil. 



3. Modiola dimidiata, S. Wood. Tab. XIII, fig. 5. 



Spec. Char. M. testa tenui, depressd, subcglindraced, elongatd ; pedi-regione brevi, 

 rotundatd, valde inaauilaterali ; dimidiatim radiatd, umbonibus depressis ; marginc ventral i 

 recti usculo. 



Shell thin, depressed, nearly cylindrical, elongate ; pedal region short, rounded ; one 

 half of the shell striated or rayed, the other smooth or naked ; ventral margin nearly 

 straight. 



Length, £ths of an inch. / 



Localitg. HighclifF, Barton {Edwards). 



I have seen only a single specimen of this elegant species, but it is well marked ; it 

 approaches the cylindrical and stone-eating shells called Lithodomus. The stria? cut 

 the shell diagonally into two nearly equal parts, covering the whole of the siphonal region 

 and extending from the umbo to the extremity of the margin, the other half of the shell is 

 free from these markings, with the exception of the extreme margin on the pedal side, 

 which has a few rays or ridges. 



