VI. DESCRIPTION OF A NEW GENUS AND SPECIES OF 

 TORTOISE FROM THE JURASSIC OF COLORADO. 



By O. p. Hay. 



Probaena gen. nov. 



This genus and species is based on a single specimen, which was 

 collected in Jurassic deposits, more specifically, in the lower por- 

 tion of the Morrison, or Atlantosaurus, beds, in the "Marsh Quarry," 

 on the Felch ranch, eight miles north of Canyon City, Colorado. The 

 specimen has been kindly put into my hands by Prof. J. B. Hatcher, 

 Curator of the Department of Vertebrate Palaeontology of Carnegie 

 Museum, Pittsburgh, Pa., to which institution it belongs, and by whose 

 collector it was secured in 1901. Its museum number is 917. 



A genus closely related to Baena, but with a more depressed carapace, 

 the hinder border of which is little or not at all notched. Vertebral 

 scutes broader than the costal scutes. Plastron with its hinder lobe 

 rounded. A fontanelle (permanent?) between the inner ends of the 

 mesoplastra. 



Probaena sculpta sp. nov. 



PI. Ill, Figs. I and 2. 



The specimen is a small and somewhat imperfect turtle, being repre- 

 sented by about three-fourths of the carapace and the greater portion 

 of the plastron. The length of the carapace is, at present, 105 mm., 

 and this is very near the original length. The width is 70 mm. 

 The shell has apparently been rather flat, but it was doubtless some- 

 what less so in life than at present. The greatest distance between the 

 upper and the lower surfaces is now 27 mm. The borders of the 

 carapace behind the inguinal notches are considerably flared upward, 

 but this may be due somewhat to post-mortem distortion. This border 

 appears to have been little or not at all notched, except in the midline 

 behind, where there is a slight excavation. In the nearly smooth 

 hinder border this genus differs from the species oi Baena. 



Most of the sutures and of the epidermal sulci are obscure ; and in 

 most parts of the carapace the sutures are incapable of determination. 

 The sulci bounding the second, third, and fourth vertebral scutes are 

 satisfactorily seen. These scutes have been very broad, each about 



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