598 



MOLLUSCA 



S QB-KINGDOM VI 



Diploconus, Zitt. (Fig. 1244). Guard short, obtusely conical, and having a con- 

 centric lamellar structure, not radial and fibrous. Phragmocone reaching nearly to 

 posterior end of guard. Tithonian. 



Bayanoteuthis, Mun.-Chalm. Guard long, cylindrical, mucronate, with shallow 

 lateral grooves. Dorsal area roughened. Phragmocone very slender and long, oval in 

 section. Eocene. B. rugifer, Schloenb. 



Vasseuria, Mun.-Chalm. Guard slender, elongated-conical, with three longitudinal 

 grooves extending from the apex. Alveolus over half as long as the guard. 



FIG. 1242. 



Belemnites (Actinocamax) quad- 

 ratus, Blv. sp. Upper Creta- 

 ceous ; Germany. A, Dorsal 

 view of guard with deformed 

 phragmocone projecting from 

 alveolus. B, Ventral aspect of 

 guard. C, Alveolus from above 

 (after Schluter). 



FIG. 1244. 



Diploconus belem- 

 nitoidea, Zittel. Ti- 

 thonian ; Stramberg. 



FIG. 1243. 



Belemnites (Belemnitella) mucronatus, 

 Schloth. Upper Cretaceous ; Drenstein- 

 furth, Westphalia. A, B, C, Ventral, dorsal, 

 and lateral aspects. 2/3. 



FIG. 1245. 



Beloptera belem- 

 nitoidea, Blv. Calcaire 

 Grossier; Paris Basin. 

 Ventral aspect. 



Siphonal funnels extending from one septum to the next. Very rare in Eocene of 

 Pretagne. 



Belemnosis, M. Edw. Very rare in English Eocene. 



Beloptera, Blainv. (Fig. 1245). Guard short, composed of two cones placed with 

 their apices against one another and united by a central expansion which projects 

 outwardly on either side. Anterior cone with alveolus. Phragmocone unknown. 

 Eocene. 



Belopterina, Mun.-Chalni. Like Beloptera, but without the lateral wing-like 

 expansiona Eocene. 



Family 2. Belemnoteuthidae. Zittel. 



Shell composed of a conical phragmocone and proostracum, the rostrum being reduced 

 to a thin calcareous investment of the phragmocone. Ten arms of nearly equal length, 

 each beset with a double row of hooks. Ink-sac present. Trias and Jura. 



