Shufeldt: Osteology of Lasiopyga and Callithkix. 83 



The three sacral vertebrcB are thoroughly fused together, their neural 

 spines forming a single piece, with all sutural traces obliterated. The 

 lateral processes of the first sacral vertebra make very extensive 

 articulations, on either side, with the pe!vis, the latter being of an 

 elongate form with narrow ilia and large, sub-circular obturator 

 foramina. 



With respect to the skeleton of the limbs of Aotns miriqiiouina, the 

 bones present nothing worthy of special note. But little curvature is 

 present in any of the long bones, they all being for the most pait 

 straight and slender (see Plate XVII, fig. 20, for the skeleton of the 

 pectoral limb of the left side). 



The clavicle shows the sigmoid curve very markedly, particularly 

 at the outer moiety. The blade of the scapula is flat and triangular 

 in outline. 



The pisiform is prominent and long, and when duly articulated 

 makes a right angle with the line of the shafi of the corresponding 

 ulna. 



The humerus has a length of 6.7 cm. and the ulna of 7.2 cm. 



In the pelvic limb the shaft of the femur is very straight and cylin- 

 drical, the bone having a length of 9 cm., the trochanter minor being 

 well developed, and the caput femoris hemispherical in form. 



The supracondylar sesamoids are present, and another small one 

 is found on the summit of the tibia, just above the articulation of 

 the fibu'ar head. 



For its upper two-thirds the shaft of the tibia is much flattened 

 transversely, and somewhat bowed to the front. 



The fibula is straight and slender, especially the proximal half of its 

 shaft, while its distal extremity is much enlarged to form the external 

 malleolus. 



The skeleton of the pes presents nothing peculiar, though it may 

 be said that it is of an elongate form with the metatarsal joints and 

 phalanges inclined to be quite straight and rather slender; but this 

 does not apply to the short and tapering ungual joints. 



EXPLANATION OF THE PLATES. 

 Plate XIL 

 Fig. I. Facial view of the skull, mandible included, of Lasiopyga callitrichus. 

 Left lower-mid-incisor tooth missing. (Coll. U. S. National Museum, No. 16365.) 

 Fig. 2. Facial view of the skull, mandible included, of Lasiopyga griseoviridis. 

 Several incisor teeth missing. Both figures natural size, from photographs by the 

 author.|L(C. M. Cat. Mamm. No. ^-Y".) 



