CEPHALOPODA. 



45 



Scaphitcs mjualis. 



This genus has been divided into sections, according to 

 the peculiar forms of the partitions. Philippi mentions 

 Goniatites and Ceratites of De Hann as sub-genera. 



Scaphites. Parkinson, — Shell many-chambered, sym- 

 metrical, egg-shaped, the beginning per- 

 fectly spiral, the whorls touching, ex- 

 cepting the last, which, formed by the 

 last chamber, and free from the spire, 

 stands straight out and then curves 

 itself backwards, so that the mouth is 

 opposite to the spire ; the mouth entire, 

 drawn together, and by an inner thickening still more 

 contracted ; the partitions sinuated like the Ammonites, 

 and the lobes correspond to each other. The siphuncle 

 is dorsal. — 17 species, fossil. 



Crioceras. LeveilU. (Tropaeum Sow.) — Shell many- 

 chambered, orbicular, symmetri- 

 cal ; the spire in all stages regu- 

 lar, the whorls free, not touching 

 each other ; the last chamber 

 occupies sometimes two thirds of 

 the last whorl ; the partitions are 

 like those of the Ammonites, 

 regular, in six lobes, but with- 

 out subsidiary lobes ; the si- 

 phuncle dorsal and connected. — 9 species, fossil. 



Ancyloceras. UOrb. — Shell many-chambered, 

 rolled spirally on the same 

 plane, finally prolonged into a 

 kind of curved staff ; the whorls 

 of the spire do not touch ; the 

 straight part of the shell is 

 without partitions ; these latter 



Crioceras cristatum. 



A nrijloccras spmigerwn. 



