208 Mr. G. A. Boulenger on some Jurassic and 



Euposaurus Thiollierii^ Lortet, wliicli has just appeared in 

 Dr. Lortet's splendidly illustrated memoir on the fossil 

 reptiles of the Rhone Basin (6). Althoug:!! the fossil is unac- 

 countably referred to the Rhynchocephalia, and even to 

 the family Sphenodontidge, which, in the French author's 

 classification, includes Ilomoiosaurus, there can be no doubt 

 that we have here to do with a true lizard, as is evidenced 

 by the absence of a quadrato-jugal arch and of a plastron. 

 The pleurodont dentition, the absence of supra-temporal 

 fossEB, the non-dilatation of the clavicles, are characters which 

 a])proximate Euposaurus to the Anguidae. The interclavicle 

 (" sternum " of Lortet) is unfortunately not preserved. A 

 curious oversight is noticeable in the description of this lizard, 

 the fifth toe being described as the hallux, whicli is thus 

 stated to be opposable to the other digits, whereas in reality 

 the pes does not differ from that of an ordinary lizard. 



Of still greater interest is Lortet's account and figure of 

 Pleurosaurus Goldfussii^ H. v. Meyer, likewise referred to 

 the Sphenodontidag. It is, however, quite clear that the 

 cranial characters are not Rhynchocephalian. The temporal 

 arch appears to be essentially of a Lacertilian type and to 

 correspond with what is found in the Agamid^e. But the 

 structure of the limbs is primitive, agreeing in the tibia and 

 ulna and the metatarsals with the Dolichosauria and Protero- 

 sauria ; and as the specimens described by H. v. Meyer show 

 a plastron in the form of fine riblets, which are, however, not 

 preserved in Lortet's specimen, Pleurosaurus should be 

 regarded as the type of a distinct order of reptiles, combining 

 characters of the Proterosaurian Rhynchocephalia and Squa- 

 mata, for which the name Acrosauria, proposed by H. v. 

 Meyer in 1860, may be used. 



The number of cervical vertebrse in Pleurosaurus is stated 

 by Lortet to be only five. I have to repeat the criticism 

 made above respecting Kramberger's AigialosauruSy and to 

 add that the first rib-bearing vertebra does not represent the 

 atlas ; this vertebra is not even entirely concealed in Lortet's 

 specimen. Two small bones visible behind the occiput are, 

 in my opinion, the neuroids of the atlas. By further adding 

 to the neck the two vertebrae named by Lortet first and second 

 dorsal we have eight cervicals instead of five. 



Dr. Lortet's memoir is also rich in information respecting 

 the Hhynchocephalian genera Homoeosaurus and Sauranodon 

 (which name must yield to the prior Sa.pJiceosaurus) . The 

 latter genus was very imperfectly known ; but the beautiful 

 figures and the detailed description now published leave little 

 to desire, although some important characters shown by the 



