36 EOCENE MOLLUSCA. 
Exclusive of the Beloptera anomala (Sow.), for which I have proposed the genus 
Belemnosis, only two species of Beloptera are as yet known, 1. e. B. Belemnitoidea, and 
4b. Levesquei. Both species occur in the Paris basin, and in the Eocene beds of 
England. The first has also been found at Laeken in Belgium, and at Biaritz. 
The specific characters are taken from the conditions of the lateral expansions and 
of the conical sheath. 
No. 4. BELOpTERA BELEMNITOIDEA. De Blainville. Tab. 2, fig. la—g. 
Toorn oF A FISH; (2) Guettard. 1783. Mém. sur les Glossopétres, tab. 2, figs. 10, 11, 12. 
Betoptera BELEMNITOIDEA; De Blainv. 1825. Mal. add. et correct. p. 621, tab. 11, fig. 8. 
Serra Parisrensis; Fér. et D’Orb. 1825. Tab. Méthod. des Céph., Ann. des Sc. Nat. vol. vii. 
BELOPTERA BELEMNITOIDEA ; De Blainv. 1827. Mém. sur les Bélemn. p. 111, tab. 1, 
figs. 3, 3a, 30. 
— - J. D. C. Sowerby. 1829. Min. Con. vol. vi, p. 183, tab. 591, 
fig. 3. 
BELOPTERA BELEMNOIDEA; Voltz. 1830. Obs. sur les Bélemn. p. 20. 
BeLoprera BELEMNITOIDEA ; Deshayes. 1830. Encye. Method. vol. ii, p. 135. 
a= — Keferstein. 1834. Die Naturgeschichte der ErdkGrpers, &e. 
p- 430, No. 2. 
- _— Deshayes. 1837, Descrip. des Foss. des Eny. de Paris, p. 761, 
tab. 100, figs. 4-6. 
— — Bronn. 1837. Lethea Geog. p. 1129, tab. 42, fig. 18a-6. 
— — Fér. et D’ Orb. 1839. Céph. Acetab. Seiches, tab. 3, figs. 7-9 ; 
tab. 24, figs. 11-12. 
- - Nyst. 1843. Deser. des Coq. et des Polyp. foss. &c. p. 612, 
tab. 6, fig. 2. 
= Pictet. 1845. Traite élément. de Paléont. vol. ii, p. 316; 
tab. 14, fig. 2. 
— _ Deshayes. 1845-6. 2d Edit. de Histoire Nat. &e. p. 243. 
= — D’ Orb. 1845-7. Moll. viv. et foss. vol. i, p. 308, tab. 14, figs. 1-4. 
— — J. D.C. Sowerby. 1849. Dixon’s Geol. Hist. of Bracklesham, &e. 
p. 109, tab. 9, fig. 18. 
B. testd ovato-elongatd, longitudinaliter recurvd; supra converd ; subtus concava, 
depressa ; cavitate anticd sub-cylindricd : rostro obtuso, striato: appendicibus lateralibus 
magnis, semicircularibus. 
Shell oblong, compressed; the sheath straight and nearly elliptical; the ventral 
paries considerably thickened and depressed on the medial line below the siphuncle, 
so as to present an elevated sub-quadrate ridge, bifurcated at the posterior extremity. 
The rostrum enlarges gradually for about two thirds of the length, and then diminishes 
towards the extremity, which, in young specimens, is nearly conical in form, but in adult 
ones becomes very obtuse, probably from attrition; it is inflected towards the ventral 
aspect whence the shell presents longitudinally a somewhat arched appearance. The 
