1916] The Ottawa Naturalist. 139 



necessary to give references to the place of publication of the 

 Ordovician and Silurian species, since they may readily be 

 found in Bassler's recent and exceedingly valuable "Index of 

 American Ordovician and Silurian Fossils."* In cases where 

 I have had to change the name, I have added in brackets the 

 name under which it is to be found in Bassler's catalogue: — 



Ancyropyge romingeri (Hall), Pal., N.Y., vol. 7. 



Acidaspis anchoralis Miller (Ceratocephala) . 



A. ceralepta (Anthony) {Ceratocephala). 



A. cincinnatiensis Meek {Ceratocephala) . 



A. crosota (Locke) {Odontopleura). 



A. obsoleta Van Ingen. 



.4. onealli Miller {Odontopleura). 



A. parvula Walcott {Odontopleura). 



A. quinquispinosa Lake. 



.4. trentonensis Hall {Odontopleura). 



A. vanhorni Weller. 



Ceratocephala depauperata Van Ingen. 



C. goniata Warder. 



Dicranurus hamatus Conrad. Pal., N.Y., vol. 3. 



Odontopleura arkansana Van Ingen. 



0. callicera (Hall). 



0. coalescens (Van Ingen) {Ceratocephala) . 



0. halli (Shumard). 



O. horani (Billings) {Ceratocephala) . 



0. illinoisensis Weller. 



0. narrawayi Raymond {Ceratocephala) . 



0. nodulata (Van Ingen) {Ceratocephala) . 



0. ortoni (Foerste). 



0. perarniata (Whiteaves) {Acidaspis). 



0. robina (Clarke). Mem. N. Y. State Mus. Memoir 9. 



O? brevispinosa (Foerste) f {Acidaspis). 



0? fimbriata (Hall)t {Ceratocephala). 



Museum of Comparative Zoology, 

 Cambridge, Mass. 



*Bull. U.S. National Museum, 92. 1915. 

 fNot adequately described. 



