620 



PROCEEDINGS OF THE NATIONAL MUSEUM. 



VOL. XXXV!. 



Fig. 1. — Left hu- 

 merus OF Pti- 



LODUS OltACILIS. 



Type. Anteriok 

 VIEW. Twice 



NAT. SIZE. 



The <2:lenoid fossae are broad, nearly flat, and extend well forward, 

 giving free fore and aft movement to the lower jaws. The right 

 occipital condyle is broken away, but the remaining one is broad and 

 shows that the pair were set widely apart ; the articular surface curves 

 gently outward, backward, and upward. There is a 

 distinct notch on the inferior inner border of the 

 condyle, a character also observed in some of the 

 living diprotodont marsupials. 



A nearly complete cervical, probably the sixth or 

 seventh, and parts of two or three broken caudals 

 are practically all the elements preserved represent- 

 ing the vertebral rolumn. The cervical vertebra is 

 slightly longer than broad, indicating a moderately 

 long neck. The caudals are relatively large, with 

 well-developed processes, indicating a long and 

 rather heavy tail. 



The hvmenis (see fig. 1) is incomplete, but the 

 head, the distal end, and a considerable portion of 

 the shaft are preserved. These portions show some 

 important characters. It is distinctly eutherian 

 throughout, and is very unlike that of any of the living Montremes. 

 The head is relatively large, broadly oval in outline, and well rounded. 

 The shaft is moderately long and slender, with well-developed but 

 not highly sj)ecialized deltoid ridge. The distal 

 end is moderately expanded, and the articular siir- ^.^ 



face is divided into two well-defined ridges, the v^ 



inner, or trochlea, being somewhat broader, espe- 

 cialh^ on the anterior face, than the outer, or capi- 

 tellum. The inner condyle occupies about one-third 

 of the transverse diameter of the distal end of the 

 humerus. The entepicondylar foramen is small, 

 broadly oval in outline, sijid placed close to the 

 trochlea. The olecranal fossa is deep and sharply 

 defined. 



The radius (see fig. 2) lacks the distal epiphisis, 

 but is otherwise complete. The shaft is compara- 

 tively long and slender, slightly curved, and nearly 

 round in cross section. The tuberosity for the 

 attachment of the biceps muscle is well developed. 

 The head is expanded into a broadly ellij)tical, 

 almost circular disk, with a wide transversely con- 

 vex facet for the articulation of the ulna. Its form indicates a 

 perfectly free rotation of the forearm. Another long slender bone 

 lacking the epiphypis of the distal end, and with the proximal end 

 somewhat broken, represents the ulna. 



Fig. 2. — Right ra- 

 dius OF I'TILODUS 



GRACILIS. Type. 



a, VIEW OF PROX- 

 IMAL END ; &, SIDE 



VIEW. Twice 



NAT. SIZE. 



