MEMOIRS OF THE CARNEGIE MUSEUM. : 
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PELVic ELEMENT. 
With specimen 603 in the collection of the Carnegie Museum is a portion of a 
bone which at the time of preparing my memoir on Baptanodon 
I was unable to identify but since have concluded that it represents 
the acetabular end of the ilium. ‘This end is expanded into a 
thickened head somewhat roughened on the acetabular surface. 
The shaft above the head is constricted up to the fractured end, 
both antero-posteriorly and internally. One side of the bone is 
flattened and probably represents the internal surface. The frac- 
tured end is nearly half oval in cross-section. (See (3), Fig. 11.) 
If correctly determined this is the first evidence we have of the 
character of the pelvic region in Baptanodon and it appears to 
Fie. 11. (1); ex- 
ternal view of theace. lUdicate a weak posterior extremity as compared with the strong 
tabular end of the anterior limb. It also furnishes additional evidence that Profes- 
ili f fanod 5 g Sees : p 
iliam of Baptanodon > Marsh was mistaken in his identification of the limb in the 
discus (No. 603), one i : f : = 
half natural size, a, type of B. discus (1955) ° as a posterior extremity, a question dis- 
articular end; (2), cussed in my previous paper. ‘This element resembles somewhat 
view of articular end “7: as 3 5 : : 
the ilium of Yoretocnenus californicus, a ‘Triassic Ichthyosaurian 
of same; (3), cross sec- f t 
tionofthebrokenend. described by Dr. J. C. Merriam. 
M&EASUREMENTS. 
No. 603. Greatest width antero-posteriorly of acetabular end...............-. 45 mm. 
* 603. gs & a “« fractured end ..............-.- 27 mm. 
Baptanodon robustus sp. noy. 
The type material of this species includes a fairly well-preserved pectoral girdle, 
a series of ten cervical vertebree beginning with the atlas; a second series of eleven 
vertebree from the anterior dorsal region commencing back of the point where the 
diapophysis becomes distinct from the neurapophysial articular surface ; a third sec- 
tion of eleven posterior dorsals beginning just back of the first vertebree having the 
diapophysis and parapophysis united to form a single node-like articulation for the 
single headed ribs of this region. The fourth and Jast section contains parts of 
twelve anterior caudals. These show the rapid decrease posteriorly in the size of 
the centra, which has been previously pointed out by Knight.’ : 
This specimen, No. 919, is from the Red Fork of Powder River, Big Horn County, 
° Catalogue number of Museum of Yale University. 
‘Knight, W. C., “Some Notes on the Genus Baptanodon with Description of a New Species,’? Amer. Jour. of 
Science (4), Vol. XV., 1903. 
