SUBCLASS LEPOSPONDYLIA ZITTEL, 1887. 77 



also, since it has a well-developed pectoral girdle. The limbs in all of these genera 

 are small. The third character, "apparently without pectoral and pelvic girdles," is 

 not at all a good character, since nearly every specimen of some species and almost 

 all species show evidences of pectoral girdles and a few exhibit pelvic girdles. The 

 fourth character, "vertebras with elongated centra and aborted neural spines," is 

 not a good distinguishing character, since A mphibamus, an undoubted microsaurian, 

 possesses the same vertebral characters. "Ribs slender, and barbed like those of 

 fishes " is a character which is common to several widely distinct genera. All Micro- 

 sauria possess long, slender ribs, and the barbed condition is one which is possessed 

 by only a few, Thyrsidiiim, phider peton , etc., the so-called "barb" being merely a 

 highly exaggerated tuberculum. The teeth of nearly all Microsauria are smooth, 

 so that the character "teeth smooth" is not a good one for a group definition. It 

 has not been possible to examine any of the American specimens for the plication 

 of the dentine, since the forms are so rare and the fossils very fragile. The last 

 character, "external gills probably persistent, " is certainly not true for the American 

 species, and the evidence for the European species is negative. Fritsch described 

 and figured (Fauna der Gaskohle, Bd. i, 1883, p. 114, Tafeln 18 and 23) structures 

 which he regarded as supporting structures for the external branchiae. He says in 

 regard to these structures: 



" Bei dem Umstande, dass sie von der Kiemengegend aus sich biischelformig verbreiten 

 und man ihren Contakt mit einer Art von Branchiae constatiren kann, zweifle ich nicht 

 daran, dass diese Stabchen dem Kiemenapparate angehoren. Bedenklich ist nur ihre 

 grosse Zahl und das Vorkommen bis zum i6ten Wirbel und ich erwog die Moglichkeit, dass 

 diese Stabchen einem zarten Bauchpanzer angehoren konnten. Da aber weiter im Verlaufe 

 der ganzen Wirbelsaule nichts Aehnliches vorkommt, so ist man gezwungen anzunehmen, 

 dass Dolichosoma sehr grosse lange Kiemenbuschel besessen haben muss." 



John Samuel Budgett (79, p. 162), in his discussion of the " Structure of the Larval 

 Polypterus, " refers to the above-described specimen of "aistopodous Stegocephali, " 

 i.e., Dolichosoma lotigissimum Fritsch, and calls especial attention to the similarity 

 of the external rod of segmented cartilage on the hyomandibular of Polypterus to 

 this structure, to which Fritsch has assigned a branchiate nature in Dolichosoma. 

 There is no doubt in the mind of the present writer, however, that the rod of carti- 

 lage, referred by Fritsch to the gills, can be other than scutellate rods of the ventral 

 armature, these rods belonging to the armature of the breast or throat. The evidence 

 for this conclusion is furnished by Fritsch himself (Fauna der Gaskohle, Bd. I, plate 18, 

 fig. 1 1 ) , where all may read in the figure of the specimen the facts of the case. There 

 is quite evidently no justification for Fritsch's conclusion of the branchiate nature of 

 Dolichosoma. There is no evidence of any gill-like structure in the American snake- 

 like amphibians of the Coal Measures. 



Reviewing, then, the characters of the group which have been assigned by vari- 

 ous observers, it will be seen that there is but a single character which holds good: 

 "body long and snake-like." This is totally insufficient for the retention of the 

 group. I therefore propose to abolish the group entirely from zoological classifica- 

 tion. It is not even a family. It will, however, be convenient to refer to the snake- 

 like forms as "aistopodous." 



