116 



PROCEEDINGS OF THE NATIONAL MUSEUM. 



VOL. 50. 



Family BAENIDAE. 



BAENA ANTIQUA Lambe. 



Plates 31 and 32. 



Baeaa antiqua Lambe, Contrib. Canad. Paleontology, vol. 3, 1902, pp. 44, figa. 

 10, a, b. — Hay, Fossil Turtles of North America. 1908, pub. Carnegie Institu- 

 tion, Washington, pp. 62-G3, text-figs. 37, 38. 



A Baenid turtle acquired by the United States National Museum 

 from Mr. C. H. Sternberg is here provisionally identified as per- 

 taining to Baena antiqua Lambe. Except for its smaller size, in 



so far as a comparison can be 

 made with the rather fragmen- 

 tary type of the species, it shows 

 close similarity in nearly all de- 

 tails. If the identification is cor- 

 rect, as there is reason to be- 

 lieve, the specimen before me is 

 of importance in contributing 

 much to our knowledge of the 

 skeletal anatomy of this little 

 known species. 



The specimen. No. 8801, U.S. 

 N.M., consists of the almost com- 

 plete carapace and plastron, the 

 latter lacking the anterior lobe. 

 It was collected by Bruce Mc- 

 Kee in 1917, 3 miles below Steve- 

 ville on the Red Deer River, 

 Province of Alberta, Canada, in 

 the Belly River formation, Upper 

 Cretaceous. 



The carapace is broadly 

 rounded in front with a nar- 

 rowed and truncated posterior 

 extremity. It has an extreme length at the center of 222 milli- 

 meters, whereas Lambe estimates the type as being 290 milli- 

 meters in length. The greatest breadth of No. 8801 is 167 milli- 

 meters which is slightly forward of the inguinal notches. In most 

 Baenids the greatest transverse diameter is posterior to this notch. 

 From the inguinal notches the sides of the carapace round in rap- 

 idly to a shallow indentation half way to the posterior end, there 

 less rapidly to the straight truncated end. Except for the one 

 indentation mentioned above there are no scallops on the posterior 

 margins. There is a slight median projection of the nuchal plate on 

 the anterior border which is also slightly undulating, as in the type 



Fig. 1.— Carapace of Baena antiqua I,ambe. 

 No. 8801, U.S.N.M. C.l. C.8., costal bones 



ONE AND eight; N. 1, 2, 3, 4, 5, 6, 7, NEU- 

 RAL BONES ONE TO SEVEN; TIM., NUCHAL; V. 1., 

 y. 5., VERTEBRAL SCUTES ONE AND FIVE. + INDI- 

 CATES POSITION OF INGUINAL BUTTRESSES. ONE 

 THIRD NATURAL SIZE. 



