208 
which they were enclosed a nearly Callovian age. Dr. Waacen 
has found, however, that some of the Indian species range 
through the larger part of the Jurassic series, and even re-appear 
in the upper cretaceous beds.” 
Genus Cosmocrras, Waag.—Shell flat, discoidal; sides pro- 
vided with ribs of various forms, which are all bent forward, 
and impart a highly ornamental character to the shell; spines 
and tubercles are often developed therefrom. The ventral side 
has sometimes a smooth channel in the middle, which interrupts 
the course of the ribs across the siphonal area, as in Cosm. 
Parkinsoni, Sow., and Cosm. Garantianum, v’OrB. The body- 
Fie. 67.—Cosmoceras Jason, Reinecke. 
chamber is about half the length of a whorl. The mouth- 
border develops lateral auricles in youth, which disappear in 
old age. The suture line is very much ramified. The siphonal 
Ee 
