286 Proceedings of the Royal Physical Society. 
must be incorporated with B. major, the latter must be 
separated from the northern species. To this form I now 
apply the term leptochirus. 
B. leptochirus, n. sp. Plates of body rather thin, exposed 
surfaces covered with a rather delicate reticulo-tuberculate 
ornament. Arms slender, the articular plate of the upper 
arm having its greatest breadth contained 34 times in its 
length, while the proportion in B. major is only 3 to 1. 
From the Upper Old Red Sandstone of Heads of Ayr, Hugh 
Miller Collection, Edinburgh Museum of Science and Art. 
List oF BRITISH ASTEROLEPIDA. 
Asterolepis maximus (Agassiz), Upper Old Red, Nairn. 
Pterichthys Mulleri, Agassiz, Lower Old Red, Moray Firth 
beds, Caithness (Achanarras), Orkney. 
Pterichthys productus, Agassiz, same as above. 
Pterichthys oblongus, Agassiz, Moray Firth beds. 
Bothriolepis major (Agassiz), Upper Old Red, Scat Craig, 
Alves, and other localities in the neighbourhood of 
Elgin. : 
Bothriolepis hydrophilus, Agassiz, Upper Old Red, Dura Den. 
Bothriolepis macrocephalus (Egerton), Upper Old Red, Farlow, 
Shropshire. 
Bothriolepis obesus, Traquair, Upper Old Red, Jedburgh. 
Bothriolepis leptochirus, Traquair, Upper Old Red, Heads of 
Ayr. 
Microbrachius Dicki, Traquair, Lower Old Red, John a’ 
Groats. 
