76 THE OLD RED SANDSTONE. 
common. It seems relieved into ridges that drop adown tt 
like sculptured threads, some of them entire, some broken, 
some straight, some slightly waved, (see Plate V., fig. 3;) and 
hence the name of the ichthyolite. The plates of the head 
were ornamented in a similar style, but their threads are so 
broken as to present the appearance ef dotied lines, the dots 
all standing out in bold celief. My collection contains three 
varieties of this family ; one of them disinterred from out the 
Cromarty beds about seven years ago, and the others only a 
little later, though partly from the inadequacy of a written 
description, through which I was led to confound the Osteole- 
pis with the Diplopterus, and to regard the Glyptolepis as 
the Osteolepis, I was not aware until lately that the discovery 
was really such; and under the latter name I described the 
creature in the Witness newspaper several weeks ere it had 
received the name which it now bears. It was first intro- 
duced to the notice of Agassiz, in Autumn last, by Lady Cum- 
ming of Altyre. The species, however, was a different one 
from any yet found at Cromarty.* 
The Cheirolepis, or scaly pectoral, forms the representative 
of yet another family of the Lower Old Red Sandstone, and 
one which any eye, however unpractised, could at once dis- 
tinguish from the families just described. Professor ‘Traill 
of the University of Edinburgh, a gentleman whose research- 
es in Natural History have materially extended the bounda- 
ries of knowledge, and whose frankness in communicating 
information is only equalled by his facility in acquiring it, 
was the first discoverer of this family, one variety of which, 
the Cheirolepis Traillii, bears his name. ‘The figured speci- 
* There are three species of Glyptolepis — G. elegans, G. leptopterus, 
and (7. microlepidotus. 
