TRANSACTIONS OF THE SECTIONS. 103 
the middle of the joint, and approximate at the fore and back ends of the joint. As 
the back ends of the two lateral ridges are on the same transverse line, and the front 
end of the inner ridge rises higher upon the shaft than that of the outer ridge, this 
is by so much the shorter of the two. The low middle ridge is much shorter than 
either of the lateral ones, being confined to the lower and middle part of the trochlea, 
to which it gives an undulating transverse outline, 
The portions of the wing-bones of the Pterodactyles of the Cambridge Greensand, 
here described and figured, show the same superior proportions over those of the 
great Pterodactyles from the Kentish Chalk, as do the portions of jaw-bones and 
teeth. 
The long diameter of the expanded end of the largest of the wing-bones of a 
Pterodactyle from the Cambridge Greensand is 3 inches. 
The transverse diameter of the distal end of the humerus of the Péerodactylus 
grandis, Cuv., the largest species hitherto obtained from the Lithographic Slates of 
Germany, is 1 inch 3 lines; neither the radius, ulna, nor metacarpal of the wing-bone 
of the same species presents a diameter of its largest end equalling 1 inch. 
The articular end of the long wing-bone, 3 inches thick, being most probably that 
of an antibrachial bone, and the total length of the bone, whether radius or ulna, 
being, according to the proportions of either of these bones in the Pterodactylus 
suevicus, 16 inches, the following would be the length of the other large bones of the 
wing in the large Pterodactyle to which the above-cited specimen belonged, according 
to the proportions which the other wing-bones bear to the radius or ulna in the 
Piterodactylus sucvicus :— 
ft. in. lines. 
FELUMETUS | chi ee ee endo LadiRete se tea 1.2 2 
HaMiys) 6. (sce anes tes jib ets vere gees tol 49,0 
Metacarpus or wing-finger ........ iy hoe cade LQ 
First phalanx of wing-finger.,... fat tebe Sai O 
Second phalanx of wing-finger,....,...... 1 9 O 
Third phalanx of wing-finger ..........:. 1 5 0 
Fourth phalanx of wing-finger,..... ark Spt ling 
Total length of long bones of one wing.. 10 6 O 
Supposing the breadth of the Pterodactyle between the two shoulder-joints to be 
8 inches, and allowing 2 inches for the carpus and the cartilages of the joints of the 
different bones in each wing, we may then calculate that a large Péerodactylus 
Sedgwickii would be upborne on an expanse of wings of not less than 22 feet from 
tip to tip. 
"The pithor looks forward with confidence to future acquisitions of remains of the 
truly gigantic Pterodactylus of the cretaceous periods, more especially from the 
Greensand locality near Cambridge, as a means of throwing more light on the pecu- 
liar osteology of the extinct flying reptiles. 
For the opportunities at present afforded him, he expressed grateful acknowledg- 
ments to his old and much esteemed friend the Rey. Professor Sedgwick, F.R.S.; to 
the acute and active Curator of the Woodwardian Museum, Mr. Lucas Barrett, 
F.G.S.; to James Carter, Esq., M.R.C.S., Cambridge; and to the Rev. G. D. 
Liveing, M.A., of St. John’s College, Cambridge. 
On the Skeleton of a Seal from the Pleistocene Clays of Stratheden, in 
Fifeshire. By D. Pace, F.G.S. 
The Springfield brick-works, where the only remains of the Seal family which had 
yet been discovered in any of our post-tertiary deposits* were found, are about nine 
* Since the meeting at Leeds, portions of the skulls of two seals have been found by Mr, 
Jamieson in the Pleistocene beds of Aberdeenshire, and the pelvic bones of another in the 
brick-clays of Kirkcaldy, Fifeshire. It would also appear from the Transactions of the Wer- 
nerian Society of Edinburgh, that about thirty years ago ‘the remains of a quadruped, sup- 
posed to be those of-a seal,’ were discovered in the brick-clays of Falkirk, in the upper basin 
of the Forth, 
