34 EOCENE MOLLUSCA. 



described them as the teeth of fish. Long subsequently, M. Deshayes examined 

 similar remains found in the Paris basin ; and, having observed in them characters 

 which induced him to refer them to an extinct Cephalopod nearly allied to the 

 Belemnites, he proposed the present genus for their reception. M. de Blainville, 

 whose ' Manuel de la Malacologie' was then in course of publication, and to whom 

 M. Deshayes had communicated his proposed genus, confounded with the remains 

 in question those of the so-called fossil Sepias (Belosepise) ; but in adopting the genus 

 Beloptera, he divided it into two sections, the first containing the fossil Sepiae, 

 which he characterised as species having wing-shaped appendages united at the 

 superior extremity of the rostrum ; the second section containing the true Belopterae, 

 he described as species having the appendages distinct and the cavity conical, and with 

 chambers and a siphuncle. The mistake is continued by M. de Blainville, in the 

 Supplement to his ' Memoire sur les Belemnites,' published in 1827. In 1830, Voltz 

 pointed out the differences which rendered it necessary to keep the two genera distinct ; 

 and, about the same time, M. Deshayes published, in the ' Encyclopedic Methodique,' 

 under the article Beloptere, the grounds which induced him to establish that genus. 

 Notwithstanding this publication, however, the error into which M. de Blainville had 

 fallen was repeated by MM. d'Orbigny and de Ferussac, in their ' Histoire des 

 Cephalopodes,' and by Cuvier, in his Memoir on the bones of the fossil Cuttle-fish, 

 published in the ' Annales des Sciences Naturelles.' 



Mr. Sowerby afterwards, when he adopted the genus provisionally for the curious 

 and unique fossil obtained from Highgate, which he published in the ' Mineral 

 Conchology' under the name Beloptera anomala, confined the genus to those species 

 which contained a chambered cone like the Belemnites, and referred the species con- 

 tained in M. de Blainville's first section to the genus Sepia. The absence, in the 

 Highgate fossil, of the lateral wing-shaped expansions, and of the blunt terminal 

 rostrum which characterise the two known species of Beloptera, as well as other 

 characters to which I shall hereafter refer, seems to me to require the establishment 

 of a distinct genus for the reception of those remains ; and the genus Beloptera will 

 be then confined to those species which possess lateral expansions, and which, as 

 M. Deshayes himself describes them, exhibit an entire conical and chambered cavity, 

 resembling that of the Belemnite, joined to a terminal rostrum, like that of the 

 Belosepia. 



As thus restricted, the Beloptera present, at the anterior extremity, a semiconical 

 cavity, slightly depressed on the ventral aspect, in which was contained a thin 

 calcareous layer, covering the entire inner surface. The inner cone formed by this 

 layer contained a series of transverse, regular, and exceedingly thin septa, traces 

 of which, consisting of their sutures or lines of junction with the inner sheath, are very 

 distinct. These sutures, as they approach the ventral aspect, are slightly bent down- 

 wards towards the inverted apex of the cone, and present an acute sinus-like inflection 



