88 



usual in quadrupeds. The temporal overlaps the parietal posteriorly, 

 but is overlapped for an equal extent by the parietal at the anterior part 

 of the squamous suture. 



463. A portion of the supra-occipital plate or bone of the same fcetal or im- 



mature animal. 



464. The right ex-occipital bone of the same fcetal or immature animal. 



465. The left ex-occipital bone of the same fcetal or immature animal. 



The foregoing portions of an apparently fcetal cranium were exhumed 

 with the bones of the articulated skeleton of the Mylodon robustus, and, 

 since the form of the pelvis appears to indicate that it belonged to the 

 female sex, it is probable, from the analogy of the Sloth which produces 

 one large foetus at a birth, that it may have been pregnant at the time of 

 its death. Purchased. 



466. A fragment of the scapula of a young Mylodon robustus, including the 



glenoid articulation. 



46/. A larger portion of the opposite scapula, including the spinous process. 

 From the Pampas of Buenos Ayres. Purchased. 



468. The proximal extremity of the left ulna of a young Mylodon robustus. 



From the Pampas of Buenos Ayres. Purchased. 



469. Portions of the ex-occipital bones, including the condyles, and the large 



anterior condyloid foramina of a young Mylodon robustus. 



From the Pampas of Buenos Ayres. Purchased. 



4J0. The left half of the cranium of a Megatherioid animal, probably the 

 Mylodon Darwinii. 



471. The tympanic bone of the same cranium. 



These specimens were originally described under the name of the 

 Glossotherium* , but their close correspondence with the entire cranium of 

 the Mylodon robustus, subsequently discovered, renders it most probable 



* Zoology of the Voyage of the Beagle, Fossil Mammalia, 4to, 1839, p. 51. 



