3S EOCENE MOLLUSCA. 



at which the expansions would first appear ; but their presence is indicated by a slight 

 curve in the outline caused by their origin. I do not hesitate, therefore, to attribute 

 to this species the characteristic lateral enlargements, although they are very feebly 

 developed. 



M. Deshayes, in his ' Description des Coquilles fossiles des Environs de Paris,' 

 mentions a specimen in his possession, too much mutilated for description, in which the 

 rostrum is smoother and more elongated, and the wings appear to be much narrower 

 than in B. Belemnitoidea, and not to be inclined downwards as in that species ; and for 

 which, when better known, he thinks it will be necessary to form a new species. May 

 not that specimen be referred to this species, which has been established since the 

 publication of M. Deshayes's work ? 



The English specimens of this species have hitherto been found only at Highgate, 

 and are exceedingly rare. In France, according to M. d'Orbigny, the species occurs 

 only in the lower strata of the Paris basin ; that is to say, in the sands below the 

 nummulite bed, at Thury-sous-Clermont, Gilocourt, and Cuise-Lamotte (Oise). 



The size is twelve lines long and three lines wide. 



Genus 3d. Belemnosis.* F. E. Edwards. 



Beloptera ; J. D. C. Sowerby. 



Animal unknown but supposed to be closely allied to the Belemnite. 



Shell internal, oblong, semiconical, with the apex inflected towards the ventral 

 aspect, and enlarged into an obtuse umbo, pierced by a pore on the ventral surface ; 

 the anterior part hollowed into a deep semiconical cavity extending to the pore, and 

 having the inner surface covered by two calcareous sheaths, one within the other, 

 continued over the ventral surfaces of, and enveloping, a series of transverse septa, 

 perforated by a ventral siphon. 



Testa interna, oblongd, semiconicd, apice deorsum inftecto et in umbonem obtusum, 

 for amine perforatum, dilatato ; parte anteriori in cavitatem semiconicam, profundam, ad 

 foramen tendentem, et septa transversa, siphone ventrali perforata, continentem, excavatd ; 

 cavitatis superficie duobus laminis conicis, pertenuibus, circa septa productis et ea invol- 

 ventibus, obtectd. 



The remarkable remains for the reception of which I propose the present genus 

 are described by Mr. J. Sowerby in the ' Mineral Conchology,' and are referred by 

 that author to Beloptera. M. Deshayes, in the first instance, in the ' Description des 

 Coquilles fossiles, &c.,' expressed an opinion that they could not be placed in that 

 genus ; subsequently, however, in the notice of the genus Beloptera, introduced in the 

 second edition of Lamarck, after speaking of Belop. Levesquei, he refers not only that 



* Etym. \Se\tyLvov, telum ; e»tu<ri«, conjunctio. 



