150 Miscellaneous. 



ing the characters of the existing Indian species is of weighty import 

 in the geographical distribution of Mammaha. 



Dr, Leidy, in his general remarks upon the characteristics of the 

 Niobrara fauna, observes that " One of the most remarkable circum- 

 stances, in relation with this extinct fauna, is that it is more nearly 

 allied to the present recent one of the old world than to that of our 

 own continent. From a comparison of our recent fauna and flora 

 with that of the eastern continent, the deduction has been made, 

 that the western continent is the older of the two, geologically speak- 

 ing ; whereas the Niobrara fauna would indicate just the reverse 

 relationship of age. A number of similar instances show that totally 

 different faunae and florae may be cotemporaneous, and do not neces- 

 sarily indicate different periods of existence." 



Dr. Leidy's enumeration and brief description of the genera and 

 species (op. cit. pp. 20-29) is not in exact accordance with the 

 tabular list given by Dr. Hay den, indicating their stratigraphical 

 position {op. cit. p. 157). The Ruminant forms Procamelus robustus 

 and P. gracilis, and the carnivorous Leptarctus primus, included by 

 the latter, are omitted by the former. The list given above is founded 

 on Dr. Hayden's enumeration, as being the later in date of publica- 

 tion, and probably embracing additional materials. — Proc. Acad. 

 Nat. Science of Philadelphia, 1858. 



On a remarkable Form of Rotation in the Pith-cells of Saururus 

 cernuus. By George C. Schaeffer, M.D. 



While examining the intimate structure of various plants, I dis- 

 covered, in the year 1854, a peculiar motion in some of the pith-cells 

 of Saururus ceriums, which was so different from anything before 

 described that it seemed to be quite abnormal. Continued observa- 

 tion for eight years has shown however that, for this plant at least, 

 the phenomenon is constant, while an equally long-continued ex- 

 amination of the writers on such subjects has proved that no record 

 of this appearance has ever been made. As a mere microscopical 

 curiosity the fact might be deemed worthy of notice ; but the 

 remarkable similarity to a motion which has been considered as 

 invariably connected with a distinct and peculiar vegetable function 

 seems to render its record needful for the true advancement of 

 vegetable physiology. 



The Saururus cernuus, like many other aquatic or marsh plants, 

 has a pith the cells of which are not in complete juxtaposition, but 

 separated in part by vertical air-passages which are as regularly built 

 around by the cells as a chimney is by its bricks, with this difference, 

 however, that the cells are arranged directly one above another, and 

 do not " break joint " as the bricks would in any properly constructed 

 chimney : no fault in Nature's workmanship, we should remark, 

 since the pith is a mere filling in, surrounded by a much denser and 

 more solidly built structure. 



The cells in which the above-mentioned motion occurs are not 

 those from which the party-walls of each air-passage diverge, but 



