234 Miscellaneous. 



are directed backward, as in swimming animals. The dorsal and 

 lumbar vertebra' are shorter and more numerous ; the lumbar ver- 

 tebra^ bear no ribs ; the tail represents only one tilth of the whole 

 lenf^th of the bodv, whilst in the salamanders it equals nearly the 

 half. 



The Sahoxamlirllii is very distinct from the reptiles of the Car- 

 boniferous formation which have been deserilted under the names of 

 Labynnthodonts, Ganocephali, and Microsaurians (such as Z)tH(/re>'- 

 petun, I/i/lcrpetoit, Jfif/unomus, J\irahKt ratlins, Ant/iracherpiton, Ui'o- 

 conhflus, Ceraterpetoii, S'turopleura, Molifopfiis, &c.) ; but it differs 

 less widely from lia)iic(2)s{l\'lion) Lin Hi from Ohio, 



Xow that the existence of true Batrachians in the Palaeozoic rocks 

 seems to be proved, probably no difficulty will be raised to placing 

 Raniceps among those animals, as was jjroposcd by Mr. ^Vyman in 

 1858. It is probable that liankeps bad a naked .skin, and that it 

 possessed no eutosternum, epistenmm, postorbital, or sub.s(iuamosal. 

 Nevertheless it cannot belong to the same genus as the fossils of 

 MM. Loustau and Deldle ; its vertcbnc are much more elongated, 

 its frontals are less widened, the supraoccipital is thrown less back- 

 wards, and its mandibles are more prolonged. Lastly, the animal 

 from Ohio is three times as large. 



In 1844 Hermann von Meyer described, under the name of 

 Aputeon pcdestrls, the impression of a reptile found in the Carboni- 

 ferous formation of Miinster-Appel. Notwithstanding the oi)iiiion of 

 this talented palax)ntologist, I think that it belonged to an animal of 

 the group of salamanders ; and if it were allowable to form a judg- 

 ment from an impression so vague as that of Apatcon, I should be 

 inclined to believe this fossil to be identical with SalumandreUa 

 petrolei. Thus we should be acquainted with true liatrachians in 

 the PaloDOZoic rocks of France, the United States, and Germany. 



The bituminous schists wdiich contain Salarnandnlla petrohi also 

 include remains of plants, numerous coprolites, and fishes {PaJceo- 

 nisnis). M. Loustau has communicated to me a small crustacean 

 derived from them, a series of well-ossified vertebrtc of a still 

 unknown reptUe, and a fragment of a humerus or femur agreeing in 

 size with that of Actinodon Frossardi, a curious Ganocephalous 

 reptile, also collected in the bituminous schist, at Muse, not far from 

 Igornay and Millcry, which I brought before the Academy in 1800. 



To complete the list of Palaeozoic reptiles found in Prance, I must 

 remark that M. Paul Gervais has described a reptile from the 

 Permian schists of Lodeve under the name of Aplidosuurus ; that 

 learned naturalist has shown that it is very distinct from the 

 Batrachians. — Comptes liendiwi, February lo, IbTo, p. 441. 



On the Motive Poiver of Diatoms. By Prof. J. Leidy. 



"VMiile the cause of motion remains unknown, some of the uses 

 are obvious. The power is considerable, and enables these minute 

 organisms, when mingled with mud, readily to extricate themselves 

 and rise to the surface, where they may receive the influence of 



