364 New York State Museum 



present mode of feeding. Bryozoans were locally abun- 

 dant. The Devonian deposits were full of brachiopods. 

 In no other period have they been more abundant in both 

 individuals and species, and there are many characteristic 

 forms : Gypidula, Rensselaeria, Stringoceplialus, Eatonia, 

 Tropidoleptus, Meristella, Athyris, Spirifer etc., the long- 

 hinged Spirifers being especially abundant and character- 

 istic. Pelecypods also were abundant where there were 

 favorable conditions, muddy bottoms etc. Among the 

 genera represented are Aviculopecten, Pterinea, Actino- 

 desma, Goniophora, Modiomorpha, Orthonota, Gram- 

 mysia, Cypricardella etc. Gastropods were not uncom- 

 mon but not as abundant as the pelecypods. Among 

 the genera represented are Platyceras (including spiny 

 forms), Diaphorostoma, Loxonema, Lophospira, Euom- 

 phalus, Bucanopsis, Euryzone, Phragmostoma, Ptomatis 

 etc. A minute pteropod, Styliolina, is very abundant, 

 forming limestone masses in the Upper Devonian. 

 Among the cephalopods, straight Orthoceras types and 

 coiled forms with simple sutures {Phragmoceras, Gom- 

 phoceras, Cyrtoceras) continued. The great abundance of 

 nautiloid types of the Silurian had diminished in the 

 Devonian. The ammonoid division of the cephalopods of 

 which Goniaiites is a common form comes in for the 

 first time in the Upper Devonian. These forms were 

 destined to attain extraordinary development in the Mezo- 

 zoic but the sutures in the Devonian forms are only 

 angled and ldbes are much less complex than in the later 

 ones. Another genus, Clymenia, was far more abun- 

 dant in Europe than in America. There also occurred a 

 form, Bactrites, with a straight shell, like Orthoceras, 

 but which showed its ammonoid nature in its complex 



