JSf'ova Acta Academiee Natures Curiosorum. 489 



limits of our system of living animals ? and where shall we arrange the 

 Lizards and the Crocodiles which in truth are neither Lizards nor Croco- 

 diles? With such animals ^ptt/cAus also lived. It is evident from this 

 how rich is the calcareous schist of Solenhofen in types new, but by no 

 means improbable, which may happily enlarge the boundaries of our 

 system." Dr. Meyer rejects as altogether untenable Germar's hypo- 

 thesis that these shells belonged to a fossil Lepas, and that of Bourdes 

 that they were the jaws of a fish; and combats at considerable length 

 the opinion of Dr. Riippel, who regards them as the opercula of a shell 

 in outer form resembling an Ammonite. To the animal of this shell, in 

 the aperture of which crushed specimens are not unfreqiiently found, 

 Dr. Meyer rather suspects them to have served as food. The character 

 of the strata in which they are found is treated of at some length ; and 

 an appendix adds two new forms to those previously described in the 

 paper itself. Three plates are occupied with the figures and details of 

 these several forms. 



The fourth and last section comprehends the descriptions of several 

 " New Fossil Reptiles of the Saurian Order;" an order in which the 

 authour states that he has met with so much that is peculiar that he 

 believes himself to be in a condition to give a new systematic arrangement, 

 which will be the subject of his next paper. The present is limited to 

 notices of certain new species of the Order, forming the types of three 

 new genera. The first of these he describes under the name of Racheo- 

 satirvs gracilis : it is founded on a considerable portion of the vertebra, 

 ribs, pelvis, and hinder extremity of a skeleton, in the . collection of 

 Dr. Schnitzlein at Monheim, imbedded in a block of calcareous schist 

 brought from Daiting near Solenhofen, the well-known locality o. 

 Soemmering's Crocodilus prisons and of so niany other remarkable 

 organic remains. The second, Pleurosaurus Goldfussii, Mey., is 

 founded on nearly similar portions of a skeleton, also from the calcareous 

 schist of Daiting, in the collection of Count Munster ; it is described 

 at much less length than the preceding specimen, and is not (as is the 

 case with the Racheosaurus) figured either wholly or in detail. The third 

 genus is established on a specimen in the Royal Museum at Dresden, 



