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 Sepize (Belosepize); but in adopting the genus 
Beloptera, he divided it into two sections, the first containing the fossil Sepiz, 
which he characterised as species having wing-shaped appendages united at the 
superior extremity of the rostrum; the second section containing the true Belopteree, 
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 ‘Mémoire 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 ‘ Encyclopédie Meéthodique,’ 
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. dOrbigny and de Feérussac, in their ‘Histoire des 
Céphalopodes,’ 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 e/optera, 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, jomed to a terminal rostrum, like that of the 
Belosepia. 
As thus restricted, the Beloptere 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 mner 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 
