398 Proceedings of Royal Society of Edinburgh. [sess. 
scales, which is very constant in spite of the numerous other 
variations exhibited by the large series of specimens which I have 
examined ; and the name Geikiei having been originally applied in 
error to another species, it cannot now be adopted for any member 
of the genus, so that for the more southern species I must adopt 
the name elegantulus , previously given by me to one of its varieties. 
R. delicatulus , Traq., from the same beds, is also a mere variety of 
the same species. 
Rliadinichthys macrocephalus, n. sp. — Allied to R. carinatus in 
general appearance and scale sculpture, but proportionately shorter, 
with a smaller number of transverse scale-bands, the flank scales 
rather high in proportion to their breadth, the head proportionately 
larger, and the suspensorium less oblique than in the species last 
referred to. C.S., Pumpherston ; the most common species in the 
“curly shale” worked there and at the adjacent oil work of 
Holmes. Type specimens in the collection of the author. 
Nematopty chius Greenocki , Ag. — N. gracilis , Traq., from the 
Gilmerton Black Band Ironstone, is certainly a young individual of 
this species. 
Acrolepis semigranidosus, n. sp.— -From the roof of the Dunne t 
shale at Straiton, the Edinburgh Museum possesses a slab covered 
with scales of a large Acrolepis , the sculpture of which is different 
from that of .any other member of the genus with which I am 
acquainted. These scales, which have the size and form of those 
of A. Hopkinsi (M‘Coy), are covered on their exposed area with 
innumerable closely-set fine ridges, often tortuous, and tending 
constantly to break up into tubercles ; their main direction is, how- 
ever, as usual, obliquely across the scale from the anterior margin. 
As my Elonichtliys ortholepis from Glencartholm turns out to be 
a young specimen of a large Acrolepis , there are now four species of 
Acrolepis known, or at least described, from the Carboniferous rocks 
of Great Britain, viz., — Hopkinsi , M £ Coy ; Wilsoni , Traq. ; ortholepis , 
Traq. ; and semigranulosus, Traq. 
I may here mention that I can see no radical distinction between 
the scales of the fish from the Carboniferous Limestone series of the 
West of Scotland, which I described as Acrolepis Rankinei (Ag.), 
and the scales from Derbyshire in the Woodwardian Museum, 
Cambridge, figured by M‘Coy as Holoptychius Hopkinsi. Though, 
