CEPHALOPODA. 95 



16. Cassiani, 36 sp. of veiy variable form, and remarkable for the number 

 and complexity of their lobes. Trias, Austrian Alps. 



A 



Fig. 57.* 



Ex., A. Masimiliani (fig. 57), A, Mettemichii. 

 Crioceras, Leveille, 

 Etym., krios, a ram, and ceras, a born. 

 Syn., tropaeum, Sby. 



Ex., C. cristatum, b'Orb. (pi. Ill, fig. 8), 

 Shell, discoidal; whirls separate. 

 Distr., 9 sp. Neocomian — Gault ; Brit., France. 



ToxocERAS, D'Orb. 

 Etf/m., toxon, a bow, ceras, a horn. 

 Ex., T. annulare, D'Orb. (pi. III., fig. 12.) 

 Shell, bow-shaped ; like an ammonite uncoiled. 



Dlsfr., 19 sp. Neocomian. Between this and crioceras and ancylocenis 

 there axe nmnerous intermediate forms. 



Ancyloceras, D'Orb. 

 Etym^ anculos, incurved. 

 Ex., A. spinigerum (pi. III., fig. 10). 



Shell, at first discoidal, with separate whirls ; afterwards produced at a 

 tangent and bent back again, like a hook or crosier. 



Distr., 38 sp. Inf. oolite — chalk. S. America (Chile and Bogota), Europe. 



ScAPHiTES, Parkiuson- 

 Ett/m,, scaphe, a boat. 

 Ex., S. equalis (pi. III., fig. 9). 



SJiell, at fii'st discoidal, with close whirls ; last chamber detached and 

 recurved. 



IMstr., 17 sp. Neocomian —chalk. Europe. 

 Helicoceras, D'Orb. 

 Etyrn., helix {helicos), a spiral, and ceras, horn. 

 Ex., H. rotundum, Sby, sp. pi. Ill,, fig. 11 (diagram). 



* Fig. 57. Am. Maximiliani Klipstein. (= A. bicarinatus Miinst). Trias, Hall- 

 stadt (copied from Quenstedt), A, Profile shewing tlie numerous lobes and saddles. 

 B, suture of one side ; v, dorsal saddle. 



