30 PATAGONIAN EXPEDITIONS I PALEONTOLOGY. 



The anconeal fossa is deeper than in the other contemporary armadillos, 

 while the supratrochlear fossa is of only moderate depth. 



No portion of the forearm or manus has been found, which is especially 

 unfortunate, as the humeral trochlea indicates a somewhat peculiar char- 

 acter of the ulna and radius. 



The pelvis is very much like that of Tatu. The ilium is long, slender, 

 and trihedral, with strongly everted anterior end ; the acetabular border 

 is a thin ridge, external in position, which makes the gluteal surface pre- 

 sent dorsally and the iliac surface ventrally. As in the modern genus, the 

 anterior end of the ilium is not expanded into a plate, but is much thick- 

 ened and club-like, with very rugose crista ; the suprailiac border is very 



FIG. 6. 

 Pelvis of Stegotheriuin tesselatnm, left side ; x f . 



long and is extended farther back along the sacrum than in Tatu, mak- 

 ing the ischial border much more concave, and the peduncle of the ilium 

 is relatively shorter and heavier and the sacro-sciatic foramen is conse- 

 quently smaller. The pubic border is broad, rounded and ill-defined ; 

 near the acetabulum it supports an ilio-pectineal process, which is remark- 

 ably large and rugose, though not very prominent. In no other known 

 Santa Cruz armadillo is such a large process to be found. The acetabulum 

 is large and presents downward almost as much as outward ; the dorsal 

 border is given a notched appearance by the prominence of the anterior 

 end and the articular surface is deeply invaded by the sulcus for the round 

 ligament. The ischium is short, but broad and plate-like, and has a 

 heavier appearance than in Tatn, the descending branch being much 

 broader than in the latter. In the specimen before us the ischium is com- 



