G. Baur — Palosohatteria and the Proganosauria. 311 



rhoniboidal with long distal process, nearly of the same form as 

 that of Belodon, Aetosaurus, and Proterosaurus y ilium ex- 

 panded at the upper end ; claws well developed. 



One of the most important characters of Palceohatteria 

 consists in the presence of five distinct tarsal bones in the 

 second row, one for each metatarsal. In this it agrees with 

 Stereosternum Cope, which I placed in a new order, Pro- 

 ganosauria* 



- The Mesosauridw^ are a specialized family of this order. 

 The Palceo hatter iidce on the contrary are a generalized group ; 

 they a.re Proganosauria, which gave origin to the Phyncho- 

 cephalia. 



I give now a new definition of the Proganosauria. — 

 Humerus with entepicondylar foramen ; five distinct tarsal 

 bones in second row, one for each metatarsal ; condyles of 

 limb-bones not ossified ; pubis and ischium broad plates ; each 

 set of abdominal ossicles consisting of numerous pieces. 



1. PalmohatteriidcB. 

 Characters given above. 



2. Mesosauridw. 



Skull elongate, with numerous very sharp and slender, teeth ; 

 first metatarsal the shortest, fifth metatarsal the longest bone. 

 JSTo claws. 



The Proganosauria are Reptiles with many characters of 

 the Batrachians ; the Palceohatteriidm is the most generalized 

 group among the Monoeondylia (Sauropsida). 



Some points in Professor Credner's paper need correction : 



1. There are two not three or more sacral vertebrae. 



2. The bones called "hyoids" may just as well be the epi- 

 pterygoids (columellse). If they represent hyoids, they resemble 

 these elements in Belodon and Ichthyosaurus. 



3. There is no free lacrymal in Sphenodon as figured by 

 Credner. 



4c. The quadratojugal of Sphenodon is overlooked. 



5. The so-called basisphenoid is probably the parasphenoid. 



6. The foramen in the humerus is entepicondylccr not ectepi- 

 condylar. 



7. The carpal bones of Proterosaurus are wrongly deter- 

 mined ; the bone called radial represents the first central bone. 



8. The figure of the embryo of " Monitor" is erroneously 

 explained, by both Hoffmann and Credner ; the bone called 

 tars. 5 is the metatarsal 5. 



* Baur, G-. On the Phylogenetic Arrangement of the Sauropsida. Journ. of 

 Morphol, vol. i, No. 1, Sept, 1887. 



f I use the family-name Mesosauridce. It is probable that Mesosaurus Gervais 

 is the same as Stereosternum Cope. 



