CEPHxU>OPODA. 



87 



LiTUiTES, Ereyiiius. 

 Ebjm., Utuus, a trumpet. 



Sijn., Hortolus, jMoutf. (wliirls sqiarate.) Trocliolites, Conrad. 

 Ex., L. convolvans, Sclil. L. lituus, Hisinger. 



Shell-., discoidal ; whirls close, or separate ; last chambei- pi'oduced in a 

 straight line ; siphuncle central. 



Fossil, 15 sp. Silurian, N. America, Europe. 



'Trochoceras, Ban-ande, 1848. 

 Ex., T. ti'ochoides, Bar, 

 Shell, nautiloid, spiral, depressed. 

 Fossil, 16 sp. U. Silurian, Bohemia. 



Some of the species ai-e nearly flat, and haring \hc last chamber pro- 

 duced would formei-ly have been considered Lituites. 



Fig. 45. CLymenia atriata, Munst.* Fig. iOi. C. linearis, Munst. 



Clymexia, Munster, 1832. 

 Etym., clymene, a sea-nymph. 



Syn. Endosiphonites, Ansted. Sub-clymenia, D'Orb. 

 Ex., C. striata, pi. II., fig. 16 (Mus. Tennant). 

 Shell, discoidal ; septa simple or slightly lobed ; siphuncle internal. 

 Fossil, 43 sp. Devonian, N. America, Europe. 



FAMILY II. Okthoceratid^. 



Shell, straight, cui-ved, or discoidal ; body chamber small ; aperture con- 

 tracted, sometimes exti'cmely naiTow (figs. 40, 41) ; siphuncle complicated. 



It seems probable that the cephalopods of this family were not able to 

 wathdi-aw themselves completely into their shells, like the pearly nautilus ; 

 this was certainly the case \\'ith some of them, as M. Ban-ande has stated, 

 for the siphonal apertm-e is almost isolated from the cephalic opening. The 

 shell appears to have been often less calcified, but connected with more vas- 

 cular pai'ts than in the nautilus ; and the siphuncle often attains an enor- 

 mous development. In all tliis, there is nothing to suggest a doubt of their 

 being tetrahranchiate ; and the chc\Ton-shapcd coloured bands preserved ou 

 the orthoceras anguliferus,^ sufficiently prove that the shell was essentially 

 external. 



* Fig. 45. Sutures of two species of Clymenia from Phillips' Pal. Fob., Devon- 

 shire. 



t Figtired by D'^Vicaiac and Verneuil, Geol. Trans. 



