68 Reviews: Huxley—Belemnitide. 
to prove that this important part in the Belemnitide corresponds 
with a portion only of the ‘pen’ of the Cuttlefish; and for that 
reason he gives it the special name of ‘ pro-ostracum :’ he also points 
out that, in specimens he has examined, this part presents three dis- 
tinct types of form :—1st (as in Belemnites elongatus), ‘prolonged as 
a broad spatulate plate along the whole length of the dorsal region of 
the mantle, and produced laterally and inferiorly, for an unknown 
distance, along the lateral and ventral regions of the body :? 2nd (as 
in B, attenuatus, which is probably the same as B. Owenii and B. 
Puzosianus), it is ‘very thin, apparently horny, or imperfectly cal- 
cified, in the dorsal region, and supported laterally by two thin 
calcareous bands, or pillars, which, inferiorly, expand upon the 
“conotheca :”’ 3rd (as in Xtphoteuthis elongata), very long and 
narrow, partly flat, partly subcylindrical: and, 4thly (as in a Belem- 
noteuthis in the British Museum), a different, but not yet determin- 
able, form.* 
The ‘ conotheca’ on its outside bears certain curved lines, which 
are of iraportance in the study of Belemnites, in consequence of 
their being regarded as indicative of the probable form of the edge 
(often missing) of the ‘pro-ostracum.’ These ‘conothecal strix’ 
differ very considerably in specimens hitherto observed by Voltz, 
Quenstedt, D’Orbigny, and others. Prof. Huxley remarks on this 
point :— 
‘If the arrangement of the conothecal lines indicates the form of the 
“yro-ostracum,” and vice versd, the majority of Belemnites ought to have a 
two-banded “ pro-ostracum ” like that of B. Puzosianus ; and, on the other 
hand, the peculiar arrangement of the “conothecal”’ lines of the present 
“phragmacone ” [from the Ammonites-obtusus zone of the Lias, and in the 
Rev. J. Montefiore’s Collection] ought to indicate that it was associated 
with a different kind of pro-ostracum ; and, so far, there may be ground for 
suspecting that it belonged to some of the species which have “ pro-ostraca”’ 
like that of B. Bruguierianus. But I am by no means satisfied of the jus- 
tice of Voltz’s assumption, which D’Orbigny and others adopt,—that the 
“ conothecal lines” must indicate the form of the “pro-ostracum ;” since 
the latter may readily have been modified by the deposition of shelly matter 
upon its exterior, after its first formation.’ 
Prof. Huxley demonstrates that certain true Belemnites were pro- 
vided with hooks on the arms, horny beaks, and a large ink-bag. 
These features, as well as the ‘ pro-ostracum,’ ‘conothecal striz,’ and 
* Asit seems to have escaped notice, andis certainly of interest, we may remark 
that Buffon in 1774 recognized in some well-preserved Belemnites, which he very 
clearly describes, dug up from Oolitic clay at Montbard, a sort of appendix, con- 
tinuous with the coating of the little chambered cone of the Belemnite, of a yellow- 
ish colour, calcareous in substance like the shell, extremely tender, and having the 
form of a wide flattened funnel, nearly two inches long, and tapering from one inch 
at the widest to six lines at its gunction with the Belemnite. Although Buffon could 
not decide what Belemnites really were, yet he distinctly called the attention of 
Naturalists to the fact that they had not hitherto recognized all the parts of these 
curious shells; and he suggested that this additional evidence of their structure 
might assist in determining the class to which they really belong. (See ‘ Explica- 
tion de la Carte Géol. de France,’ vol. i. p. 347, &c.) 
