252 CRETACEOUS PELECYPODA 



7^. Cyclas, Klein, 1753. Shell orbicular, moderately compressed, thin, 

 hinge-teeth generally complete, but very small, surface with regular concentric 

 strige of growth, covered with a kind of polished coating, which is angularly and 

 divaricately striated; type, Luc. divaricata, Linn. Species of this type already 

 occur in cretaceous deposits. 



List of cretaceous species. 

 a. CORBINJE, vide genus Fimbria in Pictet and Canipiclie, Pal. Suisse^ 4™*^ ser., 5"^^ liv._, p. 283. 



1. — F. corrugafa, Sow.^ is the tjpe of Sowerby^s Splimva and of Conrad^s Palceocorbis 

 (see p. 247). 



2-5. — F. gemmifera, P. and C, Michaillensis, P. and C, fibrosa, Forb.;, GauUina, P. and P., 

 are not known by the hinge-teeth; the forms agree with Corbis, excepting the first named species, 

 which may also be a Lucina (sub-genus Codakia). 



6. — F, rotundata, d^Orb., is the type of the genus Miitiella (see p. 247). 



7. — F. Verneuilli, Gueranger, [Corbis id., Album paleont. de la Sarthe_, 1867, pi. xix^ fig. 8), 

 is a small concentrically lamellated species of Mutiella. Gueranger also gives two figures on the 

 same plate of the last named species. 



8. — F. striatocostafa, d^Orb., probably belongs to the same genus as the last, or to Sph(Bnola. 



9. — F. Salignaci, Coq., not known from the hinge. 

 X 10. — F. coarctata, Ti'iit., is a Mutiella. 



11-12. — F. muUilamellosa and snblamellosa, d^Orb., uncertain. 



13. — F, Tevesthensis, Coq.^, from Algiers,, appears to be a true Corbis. 



14. — Corbis sublavis, Keys., (Petschora-reise, pi. 17, figs. 12-13,) is apparently a true Corbis, 

 and doubtfully referred by Eichwald to the Neocomien (Leth. ross., xi livr., 1867, p. 641). 



15-16. — Luc. heteroclita, d'Orb., (Eichwald, ibid. p. 647,) is a Unicardium, and the same may 

 be the case with Luc. rostrata, Eichw., (ibid. p. 649) ; both rather appear to resemble Jurassic more 

 than cretaceous types. 



17. — Unicardium inornatum., d^Orb., [Card, idem. Pal. fran9. cret., pi. 256, figs. 3-6). 



18. — Fimbriella laevigata, Sow., sp-., see p. 246. 



19-20. — 8]pli(2rella concentrica. Con., Journ. Acad. N. Sc, Ph., ii, p. 280, is from the Alabama 

 cretaceous rocks ; and Sph. Oregon, Con., is quoted by Conrad from the lower eocene (? cretaceous) 

 of Oregon, (see Check-list eocene foss.. Smith. Misc. Coll., No. 200, 1866, p. 6). 



In the South Indian cretaceous rocks the following three species occur :— 



21-23. — Mutiella exigua, Corbis typica, and oblong a ; all are from the highest beds, the Arrialoor 

 group. 



I. LVCININJE, vide Lucina in Pict. and Camp., Pal. Suisse, 1. cit., p. 290. 



24-28. — L. Germani, vermicularis, Cornueliana, Du^miiana, sin^ Roiiyana appear to be tnuQ Lucince. 



29. — L, Bobinaldina is quite uncertain. 



30.—./;. globiformis, Leym., has more the form and structure of a Mysia f= Liplodonta) 

 than of a Lucina. 



31.— Z. Urgonensis, Lor., Rech. Geol. de la Savoie, &c.,par A. Favre, tom. i, 1867, p. 377, pi. c, 

 fig. 13 j the posterior radiating striation of this species strongly recalls Linearia, (Tellinid^). 



32. — L. ? solidula I would suspect to be a Mysia. 



33-34. — L. Yaldensis and sculpAa are apparently true LucincB. 



35.— X. Vibrayeana has the external form of the sub-genus Myrtea of Lucina. 



36-37.— i^. Banct(E-crucis and Arduennensis may rather belong to Mysia than to Lucina. 



38.— Z. ? orbicularis, Sow. ; this looks more like a Limopsis than a Lucina. 



39. — L, pisum is a true Lucina, 



