BELEMNOSIS, BELOPTERA, SPIRULIROSTRA. 203 



Genus CONOTEUTHIS, d'Orb. 



C. DUPINIANUS, d'Orb. PI. 95, fig. 462. Neocomian of France. 

 Only species. 



Genus BELEMNOSIS, Edwards. 



B. PLICATA, Kdwards. PI. 95, fig. 463. Eocene, London. Only 

 species. 



Genus BELOPTERA, Desli. 



Four species. Eocene of Paris and Bracklesham. 

 B. BELKMNITOIUKS, Blainv. PI. 95, figs. 464, 465. Paris. 



(i'lins SPIRULIROSTRA, d'Orb. 



S. BELLARDTI, d'Orb. PI. 95. fig. 466. Tertiary of Turin. 

 Only species. 



Family XIV. SPIRULID.K. 



Genus SPIRULA, Lam. 



Although thousands of shells of these pelagic mollusks are 

 washed ashore in all parts of the world, the animal is almost un- 

 known ; but two perfect specimens having been obtained in New 

 Zealand, which, with two or three of other individuals in bad 

 condition, have been carefully examined by Prof. Owen and 

 others. 



Prof. Owen's last memoir on the Spirvla adds materially to 

 what was heretofore known respecting this strange animal.* He 

 shows that the mantle terminates posteriorly in two lateral flaps 

 which cover the sides of the shell, and leaving it partly ex- 

 posed dorsally and ventrally. Posteriorly, between the lobes is 

 an elliptical convex body with a central depression or disk, 

 flanked by a pair of oblong productions, perhaps homologous 

 with fins, or at any rate resembling the small lateral-terminal 

 fins of Loligopsix. The terminal disk is, perhaps (as long ago 

 described by Rumphius), a true sucker, enabling the animal to 



* Ann. Mag. Nat. Hist., 5 ser., iii, 1, 1879. 



