31 G PROCEEDINGS OF THE NATIONAL MUSEUM. vol.38. 



BASILEMYS NOBILIS, new species. 



Among the turtle remains collected by Messrs. Gardner and 

 Gidley at Ojo Alamo, New Mexico, are some portions of a species of 

 Basilemys. These remains were found below the upper conglomerate 

 bed, in the dinosaur-bearing deposits and about 50 feet above the 

 lower- conglomerate. There are many fragmentary parts of both 

 the carapace and the plastron, but the most important part is the 

 border of the right side of the hinder lobe of the plastron, including a 

 portion of the hypoplastron and a part of the xiphiplastron. The 

 lames present indicate a large turtle, one of nearly the size of the type 

 of Basilemys variolosa, the type of the genus, the plastron of which 

 was about 670 mm. long. The catalogue number of the type of 

 Basilemys nobilis, here described, is 6555. 



The right extremity of the fragment of hypoplastron reaches out 

 to the suture with the eighth peripheral. From this suture to that 

 between the hypoplastron and the xiphiplastron, following the curve, 



is 102 mm. Near the 

 former suture the bone 

 is 52 mm. thick. From 

 the border of the ingui- 

 nal notch a wall extends 

 backward along the 



,„ ,„ „ , ,„ border of the hinder 



Figs. 12, 13. Basilemys nobilis. x$. 12, section across free 



BORDER OF XIPHIPLASTRON 10 MM. BEHIND HYPOPLASTRON; ON lODC At the llVpO- 

 THE LEFT THE SECTION ENTERS DEPRESSION FOR PUBIS; 13, SECTION xil )ll h)l "istl"! 1 SU t U IV t ll IS 

 \< K'iss FREE BORDER OF XIPHIPLASTRON 115 MM. BEHIND HYPO- . 



plastron. wall rises 10 mm. above 



the lower surface of the 

 plastron. From the summit of the wall the bone slopes downward 

 rapidly and about equally on the outside and the inside of the wall. 

 Where the slope ceases on the inner side of the wall the xiphiplastron 

 is about 17 mm. thick. Passing backward 40 mm. the wall is somewhat 

 higher, slightly steeper on the outside and overhanging on the inner 

 side (lig. 12). At a. distance of 60 mm. behind the hypo-xiphiplastral 

 suture the wall is 36 mm. high and still more overhanging on the 

 inner side. At the base of the wall here the thickness of the xiphi- 

 plastron is 21 mm. As the rear of the xiphiplastron is approached 

 i lie wall becomes lower, only 25 mm. where the fragment ends (fig. 

 13). On the upper surface of the xiphiplastron there is a large oval 

 scar which was occupied by the pubis. 



On the lower surface of the oilier extremity of the hypoplastron 

 are >een the narrow thread-like sulci which bound the inguinal scute. 

 This is only 25 mm. w ide and it is thrown well out on the extremity 

 of the I.,. ne. In /;. variolosa this scute is much wider and extends 

 medially to the free border of the hinder lobe. On the sloping 



