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XVIII. Supplementary Observations on the Structure of the Belemnite and Belemno- 
TEUTHIS. 
By Gideon Algernon Mantell, Esq., LL.D., F.R.S., F.L.S., 
Vice-President of the Geological Society, 8^c. 
Received November 5, 1849, — Read February 14, 1850. 
As several eminent naturalists have expressed doubts of the correctness of my in- 
terpretation of some of the facts described in the Memoir on the Belemnite and 
Belemnoteuthis, published in the Philosophical Transactions, Part II. 1848, I am in- 
duced to lay before the Royal Society the following additional observations in con- 
firmation of the opinions advanced in my previous communication on this subject. 
That distinguished naturalist, Mr. J. E. Gray, has especially controverted my state- 
ment that the phragmocone of the Belemnites of the Oxford Clay^ possessed a pair 
of elongated shelly processes, which extended beyond the peristome or upper border 
of the conical chambered shell; the aperture resembling in this respect that of cer- 
tain species of Ammonites-I-. In the recently published ‘‘ Catalogue of the Mollusca 
in the Collection of the British Museum\',' Mr. Gray remarks, “Dr. Mantell has 
figured a specimen which appears to have an elongated process on each side, like the 
processes on the sides of the mouth of certain Ammonites; but on examining his 
specimen I am very doubtful if this appearance does not arise from an accidental 
fracture of the upper part of the conical shell.” 
Since the publication of my former Memoir, three Belemnites with phragmocones, 
in which the parts in question are unequivocally manifest, have come under my ob- 
servation. Two of these interesting fossils are in the Gallery of Organic Remains in 
the British Museum: the third is in my possession. In addition to these examples, 
evidence in proof that this structure is normal, and not the result of accident, has 
been afforded by numerous detached portions of belemnital phragmocones from the 
Oxford Clay and Lias, which display well-defined vestiges of the expanded bases of 
these processes: and that eminent palaeontologist, Mr. John Morris of Kensington, 
informs me that he has recognized their presence in specimens from various strata 
and localities. 
In the three examples above mentioned, that part of the process which extends 
* The species of Belemnite to which my observations refer, Mr. Morris informs me is Belemnites Puzo- 
sianus of D’Orbigny, £. Owenii of Mr. Pratt. 
t Philosophical Transactions, 1848, Plate XIII. fig. 3. p. 181. 
t Part 1, Cephalopoda Antepedia, p. 124. 
3 E 
MDCCCL. 
