The Group Aistopoda Miall, 1873, is untenable.
The group Aistopoda was established in 1873 as section IX by the Committee of the British Association for the Advancement of Science, in their "Tabular View of the Classification of the Labyrinthodonts." L. C. Miall ([449], [450]) was the secretary of the committee, and the report was published in two parts. Two genera were at that time attributed to the Aistopoda, Ophiderpeton and Dolichosoma, both described by Huxley from the Coal Measures of Kilkenny, Ireland.
Fritsch ([251, pp. 107-126]) in 1883 refers to the group as "Familie" and describes 4 genera and 9 species as belonging to the group. Zittel ([642, p. 383]) refers to the group as "Familie" and places 5 genera in it. Smith-Woodward (Vertebrate Paleontology, 1898, p. 129) refers the Aistopoda to a suborder. In Eastman's translation of Zittel's Paleontology the group is called a family, "Aistopodidæ." Lydekker ([393, p. 205]) regards the group as a suborder. The writer ([469]) refers the Aistopoda to an order. The group Aistopoda has been adopted by practically all paleontologists and zoologists who have had occasion to refer to these animals.
Lydekker ([393]) in 1890 defined the group as follows:
"Body long and snake-like, without limbs, and apparently without pectoral or pelvic girdles. Vertebræ with elongated centra and aborted neural spines. Ribs slender, and barbed like those of fishes. Teeth smooth, without plications of the dentine. External gills probably persistent."
MOODIE
Fritschia curtidentata Dawson. Above: Bones of skull and anterior extremity, and bony rods of belly. Below: Bones of pelvis and posterior extremity. Nearly natural size. Erect tree, Coal formation, South Joggins, Nova Scotia. Photograph by Dawson, published through the courtesy of Dr. Arthur Willey. Original specimen in the Peter Redpath Museum of McGill University.