A. Smith Woodward — JS'otes on Argentina. 21 



northern hemisphere, the stage of evolution of these Patagoniaa 

 faunas is much higher than any termed Eocene either in Europe 

 or North America. I should therefore like to add a few new- 

 observations bearing upon the subject, which I was able to make 

 during a visit to Argentina last autumn. Thanks to the kindness 

 of the brothers Ameghino, I had the privilege of examining their 

 unique collection, and Seiior Florentiuo Ameghino gave to me (for 

 the British Museum) the few fish-remains he possessed from the 

 formations described. Dr. Moreno and Dr. Santiago Koth permitted 

 me to study the collections in the Museum of La Plata, and Dr. Carlos 

 Berg will shortly transmit to London for determination the series of 

 fish-remains from Chubut and Parana now in the National Museum 

 at Buenos Aires. Complete descriptions will appear later, but it is 

 now opportune to make some pi'eliminary remarks. 



Firstly, as to the red sandstones with Dinosaurian remains, it may 

 be added that Dr. Santiago Eoth has recently brought back from the 

 Territory of Neuquen a fine collection of the small uudescribed 

 reptilia to which Seiior Ameghino refers (p. 10). One of these is 

 a typical and apparently fully-evolved snake, which I had not 

 time to study in detail. The others are small Crocodilia, of 

 which I have prepared a description now being printed for the 

 " Anales del Museo de La Plata." These crocodiles are particularly 

 interesting because they are typically Mesosuchian, with the 

 characteristic palate and amphicoelous vertebral centra. They seeiu 

 to be most closely related to the small Purbeckian Theriosuchiis and 

 its allies, differing, among other features, in their more highly 

 specialized dentition. Nearly all of them may be comprised in 

 a new genus, which I have named Notosuchus. The skull is short 

 and broad, with a much abbreviated rostrum, and the outer bones 

 are externally rugose. The supratemporal fossae are of moderate size, 

 longer than broad ; the orbits are relatively very large, directed both 

 superiorly and laterally, and with a very slender internal post- 

 orbital bar; a small antorbital vacuity occurs between the lachrymal 

 and maxillary bones ; and the nasals reach the single large narial 

 opening, which is directed forwards. The mandible is slender, 

 biting within the upper jaw, and its articular end is not curved 

 upwards; there is a large vacuity in the side of each ramus, and 

 the splenials enter the short pointed symphysis. The teeth are few 

 in number and laterally compressed, some also feebly serrated ; the 

 series of the upper jaw is much differentiated, comprising two or 

 three small " incisors " and one very large " canine " in each pre- 

 maxilla, and seven teeth of more uniform size in each maxilla ; 

 while the series in the lower jaw comprises ten teeth on each side, 

 these gradually increasing in size backwards and without any 

 " canine." The limbs are typically crocodilian in every respect, 

 and the fore-limb is not much smaller than the hind-limb. No 

 dermal armour has been discovered with any specimen. The typical 

 species, Notosuchus terrestris, has a skull about 0-15 m. in length. 

 A second, closely-related genus, Cynodontosuchus, also exhibits the 

 highly specialized dentition, but has large canines in the lower jaw, 



