300 Dr. H. Burmeister on Glyptodon and its Allies. 



is composed of Jive anchylosed vertebrae. It consists only of 

 fou7', namely the second to the fifth ; and the sixth is free ; but 

 the seventh is united with the first and second dorsal vertebrae 

 to form a large piece, which Professor Huxley has named the 

 trivertebrated bone, and M. Serres the " os metacervicale.^' This 

 piece has always the same general construction in the four dif- 

 ferent species of which well-preserved examples are now before 

 me ; but the mesocervical bone is not always composed of four 

 vertebrae, but in some cases of five. The sixth vertebra is then 

 united with the four preceding ones, in the same way as these 

 with each other, and the animal has no free vertebra between the 

 meso- and metacervical bones. 



Out of the four specimens of necks which I have seen belong- 

 ing to the same number of distinct species of Glyptodon, only 

 one is constructed in this way, of live united vertebrae ; the other 

 three have only four vertebrae anchylosed. 



As we have other portions of the skeletons of these same indi- 

 viduals with scales of the carapace, I can affirm with certainty 

 that these three species with four anchylosed vertebrae have a 

 short conical tail with large rings of conical tubercles, exactly of 

 the form described by me in the species which I have named 

 G, spinicaudus. As this is the case, I have decided to abandon 

 my first name, as indicating not a specific, but probably a generic 

 character, and to supply another name of more specific significa- 

 tion. Among the species described by other authors, I find in 

 the work of M. Nodot on Glyptodon (which was unknown to me 

 when I wrote my observations) that this author has formed 

 those with short conical tails of tuberculated rings into his genus 

 Schistopleu7'um ; that his first species, S. iypus, which is very 

 fully described, is the same that I had named in our museum 

 G. elongatus, on account of the narrow and elongated form of 

 the carapace, and especially of the pelvis ; that the second spe- 

 cies, S. gemmatum, Nod,, which has the surface of the carapace 

 much smoother, was therefore named by myself G. lavis; and 

 that the third species, described by me as G. spinicaudus, is un- 

 known to Nodot, unless it be his G. subelevatus (p. 94, pi. 11. 

 fig. 1). As this species is smaller, and has the carapace of a 

 more spherical form and the surface of the scales very rough, I 

 now propose to name it G. asper, 



Nodot's S. tuberculatum is not a Schistopleurum, but a true 

 Glyptodon ; for I suppose the tip of the tail figured in the * Os- 

 teographie,' pi. 1. fig. 5, and copied by Nodot, pi. 8. figs. 7 & 8, 

 to belong to this species. We have in the museum here such a 

 tail as is figured in the ' Osteographie,' pi. 1. fig. 4 (copied by 

 Nodot, pi. 8. fig. 6), and I am much inclined to affirm that this 

 and the other are of the same species, the construction of our 



