122 ' MEMOIRS OF THE CARNEGIE MUSEUM 
important differences which he considered as typical are the consolidation of three 
elements into one in the third segment and the development of the abnormal num- 
ber of digits by a division of the third finger. Accompanying the description is a 
drawing of the right pectoral limb showing the paddle as retained in the matrix. 
A photograph of the same paddle is shown in fig. 23. 
The paddle probably had six digits but the greatest transverse segmentation of 
Fia. 26. Atlas, axis and third and fourth cervicles of Baptanodon marshi (‘‘S”’). Seen from the right side. 
Type specimen. One half natural size. 1. Coalesced atlas and axis. 2and3. Third and fourth cervicles. at, atlas; 
ax, axis ; d, diapophysis ; p, parapophysis ; n, paired neural arch. 
the parts preserved only shows five elements, although in the original description 
he says: “The limb that I have been studying and figured differs from the one 
published by Marsh, inasmuch as the abnormal number of digits do not appear 
until the phalanges are reached.” As the specimen does not show an abnormal 
pumber of digits it would be assuming considerable, because of the peculiar arrange- 
ment of the bones of the paddle in this form, to say definitely at what point the 
extra digit, if it did exist, is developed. Moreover it does not appear justifiable to 
compare this fore limb with the supposed hind paddle of B. discws and consider as 
specific characters differences that are almost certain to exist in the structure of 
anterior and posterior paddles. 
After an examination of the type I should consider the large element (see Fig. 
23) as due to a consolidation of two rather than three elements. An offset on the 
distal border apparently indicates the point of union. This consolidation, instead 
