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, i. e. B. Belemnitoidea, and 

 B. 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. Be Blainville. Tab. 2, fig. la— g. 



Tooth of a fish ; (?) Guettard. 1783. Mem. sur les Glossopetres, tab. 2, figs. 10, 11, 12. 

 Beloptera Belemnitoidea; De Blainv. 1825. Mai. add. et correct, p. 621, tab. 11, fig. 8. 

 Sepia Parisiensis ; Fir. et D'Orb. 1825. Tab. Method, des Ceph., Ann. des Sc. Nat. vol. vii. 

 Beloptera Belemnitoidea ; De Blainv. 1827. Mem. sur les Belemn. p. Ill, tab. 1, 



figs. 3, 3a, 3b. 



— — J.D. C. Sowerby. 1829. Min. Con. vol. vi, p. 183, tab. 591, 



fig. 3. 

 Beloptera Belemnoidea ; Volts. 1830. Obs. sur les Belemn. p. 20. 

 Beloptera Belemnitoidea ; Deshayes. 1830. Encyc. Method, vol. ii, p. 135. 



— — Keferstein. 1834. Die Naturgescbichte der Erdkorpers, &c. 



p. 430, No. 2. 



— — Deshayes. 1837, Descrip. des Foss. des Env. de Paris, p. 761, 



tab. 100, figs. 4-6. 



— — Bronn. 1837. Lethsea Geog. p. 1129, tab. 42, fig. \8a-b. 



_ _ Fir. et D'Orb. 1839. Ceph. Acetab. Seiches, tab. 3, figs. 7-9 ; 



tab. 24, figs. 11-12. 



— — Nyst. 1843. Descr. des Coq. et des Polyp, foss. &c. p. 612, 



tab. 6, fig. 2. 



— — Pictet. 1845. Traite element, de Paleont. vol. ii, p. 316 ; 



tab. 14, fig. 2. 



— — Deshayes. 1845-6. 2d Edit, de l'Histoire Nat. &c. p. 243. 



_ _ D'Orb. 1845-7. Moll. viv. etfoss. vol. i, p. 308, tab. 14, figs. 1-4. 



— — J.D. C. Sowerby. 1849. Dixon's Geol. Hist, of Bracklesham, &c. 



p. 109, tab. 9, fig. 18. 



B. testa ovato-elongatd, longitudinaliter recurvd ; supra convexd ; subtus concavd, 

 depressd ; cavitate anticd sub-cglindricd -. rostro obtuso, striato : appendicibus later alibus 

 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 



