444 
Proceedings of the Poyal Society 
and distantly jointed. Between the anal and caudal fins there is a 
considerable interval. The caudal is inequilobate, with attenuated 
body prolongation ; its rays are slender, smooth, and with distantly 
placed articulations. The fulcra are very obvious in all the fins, 
notwithstanding the small size of the fish. 
Remarks. — This species is allied to R. carinatus in general form, 
and in the large size of the scales of the flank, but differs obviously 
from it in the general larger proportional size of the scales, in the 
ornate character of those along the dorsal and ventral margins, and 
in the greater delicacy of the fins, and smaller number of their rays. 
The head seems also to be larger in proportion to the size of the fish. 
Geological Position and Localities. — A fish of the middle or 
“ Edge Coal ” group of the Carboniferous Limestone series, the speci- 
mens above described being from Wallyford, near Tranent, in the 
collections of Mr D. J. Brown ; and from Possil, near Glasgow, in 
the collection of Messrs James Thomson and John Young, F.G.S. 
To the kindness of these gentlemen I am indebted for the oppor- 
tunity of describing this most distinct and interesting little form. 
On the Cranial Osteology of Rhizodopsis, and on some points 
in the Structure of Rhizodus. By Dr B, H. Traquair. 
[Abstract.) 
Read May 21, 1877. 
This paper contains an account of the cranial structure of Rhizo- 
dopsis as far as this can be elucidated by an examination of a suite 
of specimens from the Coal Measures of Eenton, Staffordshire, in 
the collection of Mr "Ward of Longton, supplemented by additional 
specimens from various other localities. 
. 
The cranial shield of Rhizodopsis resembles in general form and 
structure that of the Saurodipterini, though the surface of the bone 
is elaborately sculptured instead of presenting the smooth glistening 
aspect characteristic of the external plates and scales of the last 
named group. The posterior part of the shield is composed of two 
elongated parietals, and having on its outer margin two smaller 
plates, anterior and posterior, which may be considered as the post- 
frontal and squamosal respectively. The anterior or fronto-ethmoidal 
