H. VON MEYER SAURIAN FROM ISTRIA. 35 



stetter's observations); in Mexico, where Von Humboldt has described 

 the phenomena just as they occur in Hungary ; greenstone-trachytes 

 being the oldest rocks, followed by grey trachytes (andesite), and 

 then by rhyolites, with the usual circumstances of siliceous concre- 

 tions in shape of opals, &c. As with those of Hungary, the Mexican 

 greenstone-trachytes are the chief bearers of auriferous and argen- 

 tiferous ores. 



[Count M.] 



On a New Fossil Saurian from Comen, Istria. 

 By Hermann von Meter. 



[Proceed. Imp. Geol. Instit. Vienna, January 31, I860.] 



A slab of stone from Comen, in the district of Goritzia, containing 

 some finely preserved remains of a Saurian, and belonging to the 

 City Museum of Trieste, has been examined by H. von Meyer, who 

 pronounces the Saurian of Comen to be a Lacertian, with concavo- 

 convex vertebra}, connected with Prof. Owen's genera Dolichosaurus, 

 Coniosaurus, and Raphiosaurus of the English Cretaceous deposits. 

 All the Lacertians of earlier periods, even those of the lithographic 

 stone, show no convexity on the posterior articular surface of their 

 vertebrae ; so that, not considering the development of the rest of 

 their structure, they would seem to bear an embryonal character. 



The Comen Saurian is but of half the size of the above-named Eng- 

 lish genera, standing next to Dolichosaurus longicollis, to which it is 

 connected by its lengthened, narrow, and cylindrical shape (thus 

 recalling to mind the recent serpen tiform genera Pseudopus, Bipes, 

 and Ophiosaurus, with imperfectly developed extremities), and by 

 its probably long neck, consisting (as some circumstances seem to 

 indicate) of a great number of vertebra?. This last character is too 

 important to be confined to a single genus ; it may be supposed to 

 have been common to several other Cretaceous Lacertians with con- 

 cavo-convex vertebral articulations, although not j'et made evident 

 by preserved remains. 



Prof. Owen infers, from two specimens found in the same locality 

 and at the same time, that his Dolichosaurus longicollis possessed 

 40 vertebrae between the neck and the pelvic region. The uncom- 

 monly well-preserved individual of Comen has only 27 vertebrae — a 

 circumstance warranting the establishment of a new genus, for 

 which H. von Meyer proposes the name of Acteosaurus (from ukt>), 

 strand, the specimen having been found in the Istrian shore, and 

 its original having probably lived along the sea-coast), with the spe* 

 cific denomination of Act. Tommasinii, in honour of the Podesta of 

 Trieste, Cavaliere Tommasini, who gave it to the museum of that 

 city. 



The anterior extremities of Acteosaurus, although folly developed, 

 are of a remarkably small size ; the length of the radius is to that 

 of the humerus as 5 to 7, to the femur as 1 to 2. The proportion 

 of the tibia to the femur is 4 to 7. The carpal and tarsal bones are 



