PLATE XIX. 



Fig 



1. VtericMhys Milleri, seen from the dorsal surface; natural size. From a 



specimen from Lethen Bar in the British Museum (50109). 



2. Dorsal aspect of head and carapace, without pectoral appendages or tail, of a 



specimen from Cromarty, in the Hugh Miller Collection, Royal Scottish 

 Museum. This is the type of Ptcriclithys testudinarius of Agassiz. Natural 

 size. o. o., orbit. 



3. Ventral view of the same specimen. 



4. Detached right ventro-lateral plate, seen from the internal aspect ; natural 



size. From Achanarras, Caithness, in the Royal Scottish Museum, Edin- 

 burgh. 



