656 



MOLLUSCA 



PHYLUM VI 



and resembles (as do also the two dorsal saddles and small dorsal lobes) those of 

 the Arietitinae. a 



■1,1 KS LSI LS^ % IS 



k M 





Fin. 1-265. 



Arii'tites hisulcatus Brug. Lower Liiis ; Wiirtemburg. A, Suture line ; IS, (\ Portion of volution .seen from 



the Lateral and ventral aspects. 



Aegoceras Waageii (Fig. 1266) 

 Hyatt has proposed the following 

 subgenera : Liparoceras, Microdero- 

 ceras and Androc/ynoceras. Lo\\er and 

 Middle Lias. 



The second group is that of Schlo- 

 fheimia Bayle, called by Hyatt the 

 " Angulatidae." This includes more 

 or less compressed and costated shells, 

 the costae sometimes crossing the 

 venter in the young or extreme age, 

 l)ut usually interrupted in the adult 

 by a smooth and occasionally sunken 

 median zone. Sutures inclined apicad 

 near lines of involution, more com- 

 plex in outline than in tyjjical Arie- 

 '■ tites, and with phylliform marginals 



Ventral lobe broader and shorter, with larger siphonal 



Fii;. ItiOt;. 



ras capricornns (Sclilotli.). Middle I^ias 

 Gniiind, Wilrtemberg. 



Aegoce 

 more like those of Psiloceras. 



