130 Reviews — Nicholson and LydeJcker' 's Palaeontology. 



sedis. Among later Amphibia, the family Hylasobatrachidas is pro- 

 posed for the Weahlen Caudate genus Eylcsobatrachus of Dollo ; and 

 the description of the Ecaudata is well up to date, though some 

 reference might have been made, at least in the table of "Literature," 

 to the recent elaborate researches of Wolterstorff. 



In the Reptilia, the great groups are arranged chiefly according to 

 the system proposed by George Baur. Four diverging " branches " 

 are recognized, and it is remarked "that the close approximation to 

 the Amphibia presented by the earlier members of several of these 

 branches suggests the idea that Eeptiles may have been derived from 

 the Amphibians by more than one line of descent." The so-called 

 order Proganosauria is thus rejected ; and " the manifest affinity of 

 [its type-genus] Mesosaurus to the more typical Sauropter3'gia, and 

 of Palceohatteria to the Khynchocephalia, seem to render it more 

 advisable to refer those genera to the two orders in question, of 

 which they will respectively form the most generalized stage." 



The Theromorous Branch of Reptiles is regarded as comprising 

 only a single order, that of Anomodontia, noteworthy for the 

 resemblance of many of its features to those of the Labyrinthodont 

 Amphibia, and of the Monotreme Mammalia. The order appears 

 to be confined to the Permian and Trias, and is subdivided into 

 Pariasauria, Theriodontia, Dicynodontia, and Procolophonia. Paria- 

 saurus is noticed as described by Seeley ; and Anthodon, also from 

 the Karoo System, is included in the same family. The gigantic 

 Anomodonts, TapinocepJialus and Titanosuchus, from the Karoo, form 

 the first family of Theriodonts, and the pelvis named Phocosaurus is 

 recorded as not impossibly referable to the former. The Placodontia 

 are placed, as a group of uncertain rank and position, between the 

 Theromorous and Synaptosaurian Branches ; and the interesting 

 fact is noted, that all known limb-bones from the Muschelkalk, in 

 which the skulls of Placodus occivr, are either Dinosaurian or 

 Sauropterygian. The Synaptosaurian Branch comprises the orders 

 of Sauropterygia and Chelonia, illustrated by numerous good figures ; 

 and the last-named order is further divided into the suborders of 

 Athecata and Testudinata (Thecophora), in accordance with the 

 researches of Cope, Boulenger, and Dollo. The opposite view of 

 Baur is mentioned, but the Athecata are provisionally adopted as 

 the more primitive (not degenerate) type; and " before a decisive 

 opinion can be given on this question, it must be determined whether 

 the absence of a bony connection in this group between the parietals 

 and pterygoids is to be regarded as an acquired or as an original 

 feature." The Streptostylic Branch comprises the orders Ichthyo- 

 pterygia, Proterosauria, Rhynchocephalia, and Squamata, and the 

 opening paragraph of the chapter relating to these is an interesting 

 study in the complexity of taxonomy and nomenclature. All the 

 Ichthyosauria are included in a single family ; and in the Addenda 

 (p. xi) the species Iehthyosaums platyodon is made the type of a new 

 genus, Temnodontosaurus. The Rhynchocephalia are divided into 

 the suborders of Simgedosauria, Sphenodontina, and Homa^osauria, 

 and Palceoliatteria is placed first in a doubtful subordinal position. 



