PLATE XXI. 



Fig. 



1. Palseoniscus comtus,' Ac/assiz. ^| Scales magnified. Marl-slate, Thrislington 



Gap. Belonging to the Natural History Society of 

 Northumberland, Durham, and Newcastle-on-Tyne. 

 Presented by Mr. T. Hodgson. 



2. Palaeoniscus longissimus, Agassiz. c, Scale magnified: Marl-slate, Thrislington 



Gap. Natural History Society of Northumberland, 

 Durham, and Newcastle-on-Tyne. Mr. T. Hodgson. 



^ All the figures are of the natural size. 



