Fig. 9. — Front lobe of the plas- 

 tron of another specimen ; 

 from Red Deer river. One- 

 half the natural size. 



44 



Additional .specimeus consist of the anterior half of a 

 plastron, parts of two other plastra, and a poorly preserved 

 carapace of small size in which, however, the convexity of this 

 half of the shell is well shown. 



The variation in the direction of the gular and intergular 

 sulci, in different individuals, to which Leidy drew attention 

 in his description of Ba'ena arenosa,* from a higher horizon, is 

 noticeable in the two Red Deer river specimens, neither of 

 which agree exactly with the type. 



Belly Eiver series, Eed Deer river, 3901. 



Baena antiqua. Sp. nov. 



Part of the carapace of an apparently uu described species of Ba'ena was obtained 

 from Red Deer river, below Berry creek, in 1901. Near it was found the anterior end 



of a plastron that, judging from the surface 

 markings, thickness of the shell, general 

 appearance and size, evidently belongs to 

 the same species and probably to the same 

 individual. 



What is preserved of the carapace 

 (figure 10, A) is in an excellent state of pre- 

 servation. Five neurals in all are represen- 

 ted with five pairs of costals. The sutures 

 are sinuous and fine but can be traced with 



ease. The sulci are 

 very distinct. 



The neurals are 

 rather irregular in 

 shape and of nearly 

 equal size. The cost- 

 als partake of the 

 same irregularity of 

 outline. The outer 

 surface is almost 

 smooth, the only 

 unevenness being 

 due to a few stria- 

 tions and depressed, 

 roughened mark- 



FiG. 10. — Baiina antiqua ; A, part of the carapace ; B, lower surface of anterior lobe of 

 plastron ; C, upper or inner surface of anterior lobe of plastron. One-haLf the natural 

 size. The sinuous lines indicate the sutures between the bones, the heavy ones the 

 boundaries of the epidermal shields. The letters are as in preceding figures. 



ings erratically disposed. Striationsalso occtir at right angles to the sutures, forming an 

 obscure border sculpture. The vertebral shields are broader than long, more especially the 

 first one. The rib-heads are well developed. There is a strong and abrupt thickening 



* Report U. S. Geol. Surv. Terrs., 1S73. vol. i. Fossil Vertebrates, pi xv, figs. 1-5. 



