Q2 THE DESEADO FORMATION OF PATAGONIA 
Of the vertebral column, twenty-six vertebra are pre- 
served (a few being represented by neural arches only). 
The atlas and axis are unknown. Five cervicals are pres- 
~ent, each with a short, slightly opisthocoelus centrum, and 
with low weak spines. The foramena for the vertebra artery 
are usually large. Cervical 3 has a rather slender trans- 
verse process, projecting down—and backward. On cer- 
vicals 4, 5 and 6, these lateral processes are enlarged into 
broad lamellae, which reach their maximum of size on the 
sixth. Cervical 7 has no lamella, simply a slender trans- 
verse process. These transverse processes are strikingly 
like those of Nesodon. The thoracic vertebrae (of which 
I have complete or in parts 15) have moderately high spines, 
which resemble those of Adinotherium, not only in the gen- 
eral build, but also in the presence of a foramen for the 
exit of spinal nerves through each neural arch. These 
foramena can not be referred to as adaptations, but are 
special features indicating close relationship with the Neso- 
dontidae. Six lumbar vertebra are present, each having 
broad depressed centra, and short wide spines. The rest 
of the column is unknown. 
The distal portion of the humerus is preserved, showing 
the trochlea to be relatively narrow, with a prominent 
internal phlange for the ulna. The epicondyles are both 
small. The supratrochlear fossa is moderately deep, the 
anconeal fossa very deep, a large perforation connecting 
the two. Of the ulna, only the distal end is preserved, and 
it is marked by a prominent styloid process, ending in the 
facet for the pyramidal, this facet continuing uninter- 
ruptedly into that for the pisiform. The two ends of the 
radius are preserved but its length can only be conjectured. 
The proximal end has a large facet for the humerus; the 
distal end two facets, for the scaphoid and luna respec- 
tively, the two being almost continuous, except as the 
outline of the shallow depressions is constricted near the 
middle. 
