178 MisceUaneou.1. 



that the primitive forms of the Caspian are freshwater animals (e. ^. 

 Dreissena polymorpht), and then that the emigrants from the gla- 

 cial sea which reached it are marine animals for the most part inha- 

 biting great depths. Hence, also, we recognize that the Caspian in 

 its fauna presents more affinities with the glacial than with the Black 

 Sea, which, again, has become richer in animals under the influence 

 of the Mediterranean. 



The Caspian has not only received species from the glacial sea, 

 but has also furnished it with some— as, for example, a species of 

 sturgeon, which seems to be Acipenser ruthenus, and lives in the 

 rivers of Siberia. T regard the Sturgeons as belonging to the 

 ancient Aralo-Caspian basin, and as having emigrated, as has been 

 said, into the glacial sea, and perhaps even to America, where, as is 

 well known, the nearest relatives of the ScaphirhyncM of the Aral 

 exist. On the other hand wc may presume that the place of origin 

 of the Acipenseridae was the Indian Ocean, and that they were 

 derived from the Selachia, with which, especially when young, they 

 have many points in common (e. g. their teeth). 



I shall only add a few remarks. The Oxus of the ancients 

 unquestionably fell formerly into the Caspian Sea. In this sea the 

 abundance of animal species is replaced by an abundance of indi- 

 viduals ; and the greater number of the species of Mollusca described 

 hj Eichwald as subfossil have been found by me in the living state, 

 and are represented by individuals as large as their fossil relatives. 

 Lastly, the deepest parts of the sea have been found to be most 

 abundantly poj)ulatcd with species of animals quite different from 

 those which inhabit the regions having only a depth of a few 

 fathoms. — Zeitschr.filr iviss. Zool. vol. xxv. p. 322, 1875 ; BibJ. Univ., 

 Bull. Sci. December 15, 1875, p. 427. 



Oil Fossil Remains of Reptilia and Fishes from Illinois. 

 By E. D. Cope. 



John Collett, the accomplished assistant of Prof. Cox of- the 

 Geological Survey of Indiana, recently submitted to my examination 

 a number of vertebrate remains from some point in Illinois. The 

 specimens were taken from a blackish shale, and consist of separate 

 vertebrae and other elements of the skeleton, often in a fragmentary 

 condition. Although the absence of information as to the mutual 

 relations of the pieces renders the identification difficult, yet the 

 interest attaching to them, in consequence of their peculiar forms 

 and the locality of their discovery, renders it important to determine 

 their zoological position. Mr. Collett informs me that all the 

 specimens were found near together, and at the same horizon, by 

 Dr. Winslow. Much credit is due to Dr. AYinslow for the pains- 

 taking labour bestowed in procuring and cleaning the specimens, 

 and for his liberality in presenting them to the geological collection. 



A remarkable peculiarity of all the vertebrae of the series is the 

 longitudinal axial perforation of the centrum. They present the 

 character observed in Arc1iego!<auyus and other steg(n'ephalous Batra- 



