REVIEWS 663 



Postorbitale den unteren Rand der einzigen Schlafenoffnung begrenzt, 

 ist sie als die oberen aufzufassen, und sie sind, im Gegensatz zu den 

 ebenfalls monozygocrotaphen Pelycosaurien und Therapsida als 'hypo- 

 zygocrotaphen' zu bezeichnen. " 



Same page, fourth paragraph: "Alle Therapsida (mit warscheinlicher 

 Ausnahme von Cynognathus) besitzen bekanntlich nur eine einzige 

 Schlafenoffnung, die der oberen entspricht (italics mine). Darin und in 

 der Forme des Quadratums stimmen sie alle mit den Deuterosaurien," etc. 



Page 43, second paragraph: "Da die untere Schlafenoffnung nicht 

 entwickelt, resp. nach unten nicht geschlossen ist, fehlt den Therapsiden 

 das Quadratojugale, " etc. 



Same page, third paragraph: "Da bei den Therapsiden das Postor- 

 bitale und Postfrontale an der oberen Ecke der Schlafenoffnung liegen, 

 ist letztere als untere Schlafenoffnung aufzufassen, die Therapsiden 

 sind also katazygocrotaph. " 



From personal conversation with Dr. Huene I know that the last 

 statement expresses his real views; but nevertheless the flat contra- 

 dictions on these two pages indicate an unsettled opinion. As I have 

 already stated {American Permian Vertebrates, p. 92) Broom has figured 

 Tapinocephalus with the postorbital and squamosal in broad contact, 

 but he nevertheless holds that the vacuity above them is the "lower" 

 one. One must therefore wait for further light on the subject before 

 accepting their views. 



And there is much confusion also about the quadratojugal bone. 

 It is known to occur in only one genus of the Therapsida, Dinocephalus, 

 but both Broom and Huene insist that it is present in the Pelycosauria, 

 and Broom has figured it in Dimetrodon. But, a study of the material 

 in the University of Chicago — material in which this region is preserved 

 most perfectly — enables me to say positively that there is no such 

 suture or foramen in the lower arch as Broom gives. That a very small, 

 vestigial quadratojugal bone may occur at the extreme posterior end 

 of the jugal is possible, but I have never seen any satisfactory evidence 

 of it, and I doubt its presence, as does also Professor Case. 



In brief my own opinion is that Broom was quite right when he referred 

 Erythrosuchus to the Phytosauria, using the term in a wide sense as a 

 synonym of Parasuchia. In any event Erythrosuchus is an archosaurian 

 reptile with no direct affinities with the Pelycosauria. 



In expressing these differences of opinion I would in no wise depre- 

 cate the value of Dr. Huene's paper. It is a useful one and may be 

 perused with profit. 



