﻿258 SIRENOIDEI. 



it appears to the present writer that the so-called C. imbricatus, 

 0. ellijoticus, &c, are founded upon variously abraded dental plates. 

 The dental plates of the Bohemian Permian variety frequently 

 exhibit one or two small posterior coronal ridges more than is 

 usual in the typical form. 



Form. § Loc. Coal-Measures : Northumberland, Yorkshire, and 

 Staffordshire, England ; Lanarkshire, Scotland. Lower Permian : 

 Bohemia. 



45852. Hinder portion of cranial roof described and figured by T. 



P. Barkas, Coal. Meas. Palaeont. p. 113, fig. 244 ; Low 

 Main Seam, Newsham, near Newcastle-upon-Tyne. 



Purchased, 1874. 



P. 3387. Imperfect bone resembling the hinder median occipital of 

 the preceding specimen ; Newsham. Ennishillen Coll. 



47478. Similar bone ; Lower Permian, Kounova, Bohemia. 



Purchased, 1876. 

 41632, 43497 a. Two opercula ; New sham. 



Presented by T. P. Barlcas, Esq., 1869, 1872. 



P. 3386-7. Two opercula; Newsham. Ennislcillen Coll. 



(i.) Palatine dental plates. 



45853, 45856. Palato -pterygoid with dental plate of right side; 



also a much abraded dental plate; Coal-Measures (Low 

 Main Seam), Newsham, near Newcastle-upon-Tyne. 



Purchased, 1874. 



41627, 48999. Two abraded examples ; Newsham. 



Presented by T. P. Barlcas, Esq., 1869, 1876. 



P. 768. Two examples, slightly abraded ; Newsham. 



Egerton Coll. 



P. 771. Right and left palato-pterygoids with dental plates ; 

 (?) Newsham. Egerton Coll. 



P. 3376, P. 3379, P. 3381. Left palato-pterygoid with dental plate ; 

 also four abraded dental plates; Newsham. 



Enniskillen Coll. 



P. 5235. Abraded left dental plate ; Coal-Measures, Tividale. 



Purchased, 1886. 



39249-50. Two dental plates ; Coal-Measures, Airdrie, Lanarkshire. 



Purchased, 1865. 



