A. H. Foord—Ascoceras Murchisoni, Barr. 121 
its cervicals and the present specimens; but a marked distinction is 
evident by the amphiccelous character of the former. There is, 
however, in the Wealden the genus Aristosuchus, which appears to 
be allied in some respects to Celurus, and of which the type may be 
taken to be the sacrum.!' Now the present specimens are much too 
large for that sacrum, and therefore clearly indicate a distinct 
species; while if the dorsal vertebra” referred to Aristosuchus be 
rightly associated, we have evidence not only of the generic, but 
also of the family distinction of the present form from the latter. 
Seeing, therefore, that we have evidence of the generic distinction 
of this form from Celurus and Tanystropheus, and also of its certain 
specific and probable generic distinction from Aristosuchus, I have 
ventured provisionally to regard it as the type of a new genus and 
species under the name of Calamospondylus Foxit. This genus 
being characterized by the opisthoccelous character of such of the 
cervical vertebre as are known, and by the much shorter length of 
these vertebrze as compared with those of Celurus. 
TX.—Nore on tHE Dectpuous Sepra or Ascoceras Murcutsonz, 
BARRANDE. 
By Arruur H. Foorp, F.G.S. 
N interesting paper has lately been contributed to this Macazinz 
(December, 1888, p. 532), by Dr. Gustav Lindstrém, of Stock- 
holm, in which he announced his discovery of the earlier, or Nautilus- 
stage, as he termed it, in several specimens of Ascoceras from the 
Silurian of the Island of Gothland. I find, however, in looking over 
the supplementary volume of the Syst. Sil. du centre de la Boheme,? 
that Dr. Lindstrém’s discovery has been anticipated by M. Barrande, 
' who observed and described two of the normal chambers (Nautilus- 
stage, of Lindstrom) attached to a specimen of Ascoceras Murchisont 
from the Silurian strata (Htage E) of Karlstein in Bohemia. I give 
here a translation of Barrande’s description, together with exact 
copies of the figures accompanying it, and the explanations of the 
same. A copy of Dr. Lindstrém’s figure is also added for compari- 
son with Barrande’s. 
“We have always assumed, especially in the original description 
of the genus Ascoceras,* that there existed below the body-chamber 
a series of deciduous air-chambers which became successively 
detached from the shell by normal truncation. This supposition is 
confirmed by the specimen which we figure on plate 491. It is quite 
apparent that fig. 3 on this plate [see p. 122. Fig. 1] represents a 
specimen which is distinguished from all those before figured upon 
our plate 95, by the relative length of the septate part which remains 
attached to the body-chamber. This septate part, when examined, 
1 Lydekker, op. cit. p. 158. R. 178. 2 Ibid. R. 178, a. 
3 Vol. ii. pt. i. 1877, Supplém. et Série tardive, p. 98, plate eccexci. figs. 3-7. 
4 Ascoceras prototype des Nautilides, Bull. Soc. géol. de France, tome xii. p. 157, 
1855. 
