620 PROF. H. G. SEELEY ON [Aug. I9OO, 



33. On an Anomodont Reptile, Aristodesmus Rvtimeyeri 

 (Wiedersheim) from the Bunter Sandstone near Basel. By 

 Prof. H. G. Seeley, F.P.S., V.P.G.S., F.L.S. (Head April 25th, 

 1900.) 



I. Introduction. 



Dr. Robert Wiedersheim, of Freiburg -im-Breisgau, has described a 

 remarkably perfect skeleton of a small reptile, which is known as 

 Labyrinthodon Butimeyeri. The remains are a natural mould of 

 the bones, in friable sandstone contained in two slabs, so divided as 

 to display in many cases the under and upper surfaces of the cavities 

 from which the bones have been dissolved away. The fossil was found 

 at Biehen, near Basel, in the Bunter Sandstone ; and is preserved in 

 the Museum of the University of Basel, Prof. Wiedersheim made 

 a restoration of the skeleton, which was published in 1878, with 

 figures of both slabs, by the Swiss Palaeontological Society. 



The animal is said to show no trace of abdominal armour, such 

 as characterizes Archcegosaurtis and most Labyrinthodonts. It does 

 not possess the breast-girdle of median and lateral sculptured 

 bones, found in Labyrinthodonts ; and the skin is inferred to have 

 been naked. The external surface of the skull, which would have 

 demonstrated its form and structure, is not available, having been, 

 as Prof. Wiedersheim states, chipped away to expose the internal 

 mould of the head. The bones are said to have been smooth and 

 free from sculpture ; and on that account the skull is compared to 

 Hylonomus of the Coal Measures. 



It was regarded as an Amphibian, in opposition to Von Meyer's 

 view that the Labyrinthodontia are true lieptilia. 1 The type is 

 unique in Europe. The original figures were unsatisfactory, and I 

 applied to the late Prof. Iliitimeyer for casts of the slabs ; but in 

 his judgment the delicate nature of the specimen did not warrant 

 the taking of impressions, which would show the bones in relief. 

 The photographs which he sent me proved the animal to be an 

 Anomodont reptile, more perfect and interesting than any speci- 

 men which was previously known, with the exception of Pareiasaurus. 

 Prof. Iliitimeyer made application to the Trustees of the Basel Museum 

 to allow me the opportunit} r of studying the remains in this country. 

 This arrangement was facilitated by the kindness of the late Sir 

 William Flower, who received the fossil on my behalf in the Natural 

 History Museum. Those most experienced in such work were 

 unwilling to take the responsibility of making moulds from the 



1 Prof. Zittel discusses the specimen in a short note in the Neues Jahrb. 

 1888, vol. ii, p. 257. He doubts the existence of* Labyrinthodont structures, 

 and states reasons why the fossil might be a reptile. Further, he quotes a 

 letter in which Prof. Wiedersheim agrees with him in regarding the fossil as a 

 reptile, and indicates some resemblance in it to lizards and to Rhynchocephalia. 

 In 1890 Prof. Zittel (' Handbuch d. Palaontologie ' vol. iii, pt. i, p. 597) suggests 

 that it is possibly Protorosaurian, classifying it under Rhynchocephalia. 



