No. 498] 



THE CAUDATE AMPHIBIA 



363 



The Stereospondyli and the Temnospondyli are spe- 

 cialized side branches of the amphibian or reptilian stem 

 and will not concern us further here. The Aistopoda are 

 regarded by the writer at present as being specialized 

 microsaurians. This would not favor the view of Wie- 

 dersheim as to the descent of the Coecilians. This point 

 needs further investigation and will be discussed else- 

 where. The Microsauria Dr. Gadow has placed in the 

 subclass Proreptiliffi and, in the opinion of the writer, his 

 classification represents the correct facts, but further dis- 

 cussion will be postponed. The group to .which the 

 reader's attention is here invited is the one usually known 

 as the Branchiosauria, representatives of which are found 

 only in Western Europe and in North America, where a 

 single specimen is known from Illinois. The group is a 

 very small one both as to the size of the individual mem- 

 bers and as to the number of species. 



The Branchiosauria are distinguished from all of the 

 other Amphibia-like vertebrates by tin 1 presence of short, 

 heavy, straight ribs. The Microsauria always have long, 

 thin, curved ribs. The Aistopoda usually are destitute of 

 ribs or when present they are curved and slight. In con- 

 versation recently with Dr. Gadow he made the interest- 

 ing suggestion that the characters presented by the ribs 

 might be used as a basis on which to separate the group 

 heretofore known as Stegocephala into two main di- 

 visions. One of the divisions would be the true Amphi- 

 bia with the Branchiosauria as the representative order 

 among the early forms, in which case the term Branchi- 

 osauria would be a misnomer, and the other Stegocephala 

 would be included under some such name as the Pro- 



