GILMORE : NOTES ON OSTEOLOGY OF BAPTANODON 331 
end is somewhat weathered and worn, and does not show the very rugose nature 
observed in better preserved specimens. The head is very conyex, the portion for 
cartilaginous attachment extending far around both anteriorly and _ posteriorly. 
There is a well developed trochanter on the dorsal surface. 
The wlna is a pentagonal block of bone, the proximal being thicker than the 
distal end. The proximal end is slightly convex and was opposed to the concave 
Fic. 8. View of the proximal end Fic. 9. Ulna of Baptano- Fic. 10. Radius of Bap- 
of the humerus of Baptanodon natans don natans (No. 1441). One tanodon natans (No. 1441). 
(No. 1441). One half natural size. d., half natural size. d.,!distal One half natural size. d., 
dorsal surface. end ; p., proximal end. distalend;/., lateral border, 
restored ; p , proximalend. 
facet on the distal end of the humerus though probably separated by cartilage. 
The other sides are slightly convex and were evidently surrounded by a thick 
cartilage as indicated by their rugose surfaces. The upper and lower surfaces are 
slightly concave antero-posteriorly. he element appears to be more angular than the 
ulna of Baptanodon marshi. 
MMNASUREMENTS. 
No. 1441. Greatest length of ulna antero-posteriorly..................200-0e0eeees 40 mm. 
“1441. coe breadthyofiual nae. eeenseececouesasecceeacemeeee cn cisec tent re ses 5O Mee 
HO el ‘* thickness of ulna, proximal end... 35) 
“1441. st ee “distal ee scennatetyssal sess se estinstiseers Bb) OC 
The radius is a sub-quadrate element somewhat wider than long and like the 
ulna thicker on the proximal than on the distal end. The external margin is miss- 
ing but apparently reduced to a comparatively thin edge. The radius is larger than 
the ulna in all of its dimensions. The proximal end is convex and was opposed to 
the largest of the three concave facets on the distal end of the humerus. The inner 
side is slightly convex, the distal flat, and all except the external side are rugose. 
The upper and lower surfaces are slightly concave antero-posteriorly. 
MEASUREMENTS. 
No. 1441. Greatest length of 1adius antero-posteriorly, estimated.............. 51 mm. 
“1441. cop breadthiofivad iusite cre cccetecnscctentes nes tceessnscsesmecee seers @ 
1441. “thickness of radius, proximal end ..................:00es0000 42 ‘* 
Go SVG a “ “ distal Sic cua erent AAU SO Mbt 30 
