GEOLOGICAL SUEYEY OF THE TERFJTOEIES. 621 



Anostiea oenata, Leidy. 



Loc. cit. 



From Bad Lauds of Upper Greeu Eiver and Cottonwood Creek. 



BAENA, Leidy. 



Geological Survey, Wyoming, 1870, p. 367 ; Survey, Montana, 1871, p. 368. Clmternum, 

 Leidy. Proceed. Academy Nat. Sciences, 1872, p. 162. 



Family Bamidce agreeing with the Adocidw* iu the presence of inter- 

 gular scuta, and the absence of coossification of the ischium and pubis 

 with the phistrou, but differing iu the presence of an intersterual bone 

 on each side, as in the Pleurodira. As generic characters, it possesses 

 two marginal intergular plates, which resemble the gulars of Emydidce ; 

 it has a series of intermarginal scuta, and the free lobes of the sternum 

 are narrowed and shortened ; the bridge is veiy wide. The dermal 

 scuta are everywhere distinct. The mesosternal bone is in form between 

 T-shaped and sagittate. The last pair of marginals, instead of being in 

 contact, are separated by a wide emargination. 



The affinities of this genus are complex and interesting. It would 

 be a pleurodire, but for the fact that the pelvis is not coossilied with the 

 plastron ; nevertheless there are rudiments of this union in the form of 

 a shallow pit on each. The posterior or °l ischiadic is near the posterior 

 end, and on the lateral margin of the i)ostabdominal bone ; it is of a 

 narrow oval form. The anterior is shallow, and sublaterally impressed 

 into the side of the upright septum, which supports the carapace. 

 "Whether it received the pubis or not is uncertain. 



The double intergular scuta is not found in any existing genus of 

 Pleurodira. ^ 



The posterior margin of the carapace is excavated, as in Glielydra, 

 but the margin is more arched iu this position in Clmternum. The 

 form suggests the presence of a large tail, and the serrate margin of 

 the carapace posteriorly reminds one again of Ghelydra. There are in 

 B. arenosa fourteen marginal scuta, without the nuchal; in Ghelydra 

 serpentina, as in Emydidce, but thirteen. 



There are jjrominent axillary and inguinal septa, as in some Emydidm. 

 They are composed of the produced edges of two coossified costal 

 bones. 



The affinities appear to be to Adocus on the one side, and Hydraspididce 

 on the other, perhaps as descendant of the former and ancestor of the 

 latter. It also possesses traces of other relationships of Adocus, i. e., to 

 Berrnatemys, and more remotely to Ghelydra. 



BAiENA HEBRAICA, Cope. 

 Baena hebraica. Proceed. Amer. Pkilos. Society, 1872, p. 463, (published July 29.) 



General form depressed and discoid, as w,ide as long. Bridge wider 

 than long, but the length equal to the width of the bases of the sternal 

 lobes. Anterior lobe longer than wide at the base, and narrowed at the 

 extremity. The inguinal and axillary septa are very prominent. The 

 edge of the carapace from the front to the inguinal region is without 

 emargination. All the osseous elements are coossified. 



The scuta are well distinguished. The unchal is very small and wider 

 than long ; the first marginal is shorter but more prominent. The second 

 and third are larger but narrow 5 the fourth and fifth are wider, but the 



* Proceed. Amer. Philos. Soc, 1870, p. 547. 



