THE JURASSIC PERIOD 



Fig. 432. JURASSIC FOSSILS, a-c, Cephalopods: a, Cardioceras cordiformis 

 M. and H.; b, Ncumayria hcnryi M. and H.; c, Bclcmnitcs densus M. and H. d-h, 

 pelecypods: d, Camptoncctes bettistriatus Meek; e, Mytilus whilei Whitf.;/, Gram- 

 matodon inornatus M. and H.; g, Pscudomonolis curia (Hall); h, Ostrea strigilcciila 

 White, i and j, brachiopods: i, Rhynchonella gnathophora Meek; j, Lingula 

 brcvirostra M. and H. 



and sturgeons were numerous, and the initial forms of the bony 

 fishes (teleosts), the dominant type, made their appearance. The 

 class was distinctly more modern than at the close of the 



Fig. 433. A Jurassic ccelacanth, Undina gulo, a crossopterygian, about 1/7 

 natural size; the outline of the air-bladder is shown just back of the gills and under 

 the axis. (Restored by A. Smith Woodward.) 



Paleozoic. Though the fishes doubtless suffered from the reptiles 

 which went down to sea in the Trias, it appears that they continued 

 in notable abundance and variety. It will be seen later that they 



