i08 CtiASSIB'ICATlON. 



Farail3r XII. BELOSEPIID.E. 



Belosepia. ( Fossil ouly. ) General characters those of the iamily. Doubt- 

 fully separable from Sepia. 



CoccoTEUTHis. (FossU Only.) Shell like Belosepia, thickened veutrally 

 by horny, instead of chalky layers. 



Family XIII. BELEMNITID.E. 



Belemnites. (Fossil only.) Animal, arms and tentacles with two rows 

 of horny hooks. Shell, phragmocone horny and slightly nacreous, with 

 a minute globular initial chamber ; two nacreous bands on its dorsal 

 side, and i)roduced beyond its rim into sword-shaped processes, repre- 

 sent the rostrum, which is fibrous, cylindrical, thickened behind, thin 

 in front where it invests the phragmocone. 



Belemnitella. (Fossil only.) Kostrum with a straight fissure on the 

 ventral side of its alveolar border ; its surface with distinct vasciilar 

 imi^ressious. Casts of the alveolus show that the i)hragmocone was 

 chambered, had a singjp dorsal ridge, and a ventral process entering 

 the fissiu'e of the rostrum. 



XiPHOTEUTHis. (Fossil Only.) Rostiaim or pro-ostracum calcareous, 

 phragmocone very long and narrow. 



AcANTHOTEUTHis. (Fossil Only.) Animal with ten nearly ecxual arms 

 with two rows of horny hooks and suckers ; margin of mantle free all 

 around ; fins large, medio-dorsal. Shell a phragmocone like Belemnites, 

 a horny dorsal pen with obscure lateral bands and a tliin fibrous 

 rostrum with two diverging dorsal ridges. 



C'oNOTEUTHis. (Fossil Only.) Phragmocone slightly curved, cliambered 

 and siphunculated, with an elongated, slender pen. No protecting 

 rostrum. 



Belemnosis. (Fossil only.) Phragmocone straight or slightly curved ; 

 rostrum rather long, thickened dorsally and obtuse at the hinder end, 

 with a ventral opening. 



Beloptera. (Fossil only.) Shell straight, rostrum sometimes winged 

 on the sides, bluntly beaked at the hinder end. 



Spikulirgstra. (Fossil only. ) Phragmocone commencing with a spiral 

 like Spirilla, afterwards continuing straight ; external spathose layer 

 produced posteriorly into a long, pointed end. 



IIeIjICEKUS. (Fossil only.) Shell like Belemnites, half iiicli in diameter ; 

 guard thick, subcyliudrical, fibrous ; pliragmoconc sleuilci-, teiminating 

 in a fusiform spiral nucleus. 



Family XIV. SPIKULID.E. 



SriRDi>A. (Recent.) Characters those of the family. 



