ke 
Reviews: Huxley—Belemnitide. 67 
supply, &c.; but without that his pages are quite full enough of 
good sound Geology, based on well-observed facts and judicious 
reasoning. 
THE STRUCTURE OF BELEMNITES, WITH AN ACCOUNT OF A NEw 
Genus (Xiphoteuthis.) By Professor Hux.ey, F.R.S., &e. 
Memorrs OF THE GEOLOGICAL SURVEY OF THE Unitep Kinepom. FicurEs AND 
DuscrietIons ILLUSTRATIVE OF British OrcGanic Remains, Monograph II. 
8vo. Accompanied by three folio Plates. 1864. London: Loneman & Co. 
ps Memoir conveys the results of the Author’s careful obser- 
vations on the structure of the Belemnitidz as shown by more 
complete specimens of Belemnites* than previously described, and 
comprises an account of his new genus Xiphoteuthis, founded -on 
some nearly perfect specimens lately discovered by Mr. Day in the 
Lias of Charmouth. 
Of all the extinct forms of animal life, few perhaps have received 
more attention than the Belemnite and its allies,—a group charac- 
terising the Secondary strata. Without entering into the intricate 
book-history of these curious fossils, noticed even by P. Belon and 
G. Agricola (1552-58) under the name of ‘ Belemnites,’ Mr. Huxley 
has selected the more recent and important observations bearing 
upon the structure of the Belemnite, and its relationship to existing 
Cephalopods,—namely, those by Buckland (1829, 1836), Voltz (1830, 
1836, 1840), Miinster (1830), Agassiz (1835), Quenstedt (1839, 
1849, 1852), Duval Jouve (1841), D’Orbigny (1842), Pearce and 
Cunnington (1842), Owen (1844), Mantell (1848), Woodward (1851, 
1856), and Pictet (1854). 
The Belemnite, as usually found, consists simply of the well- 
known subcylindrical calcareous fossil so called (the ‘ Thunderbolt,’ 
‘St. Peter’s Fingers,’ &c. of peasants) This is the ‘guard’ or 
‘rostrum,’ with a conical cavity (‘alveolus’) at its broader end, con- 
taining a conical series of numerous chambers (‘loculi,’ Huxley), 
enclosed in a thin shell-wall (‘conotheca,’ Huxley), and traversed 
vertically ono ne side (middle of the ventral) by the ‘siphuncle.’ This 
chambered portion is the ‘ phragmacone’ (Owen). Continuous with 
the upper part of the ‘ conotheca,’ is sometimes found a thin shelly 
substance (‘ pro-ostracum,’ Huxley), which has been the subject of 
much discussion, as to its presumed identity with the ‘pen’ or 
‘osselet’ of the recent Cuttlefish. ‘According to Dr. Buckland, this 
part is a corneous, or shelly, and more or less completely nacre- 
ous extension forward of the lip of the “ phragmacone.” Accord- 
ing to Agassiz, it isa “pen” identical with that of the so-called Lo- 
lige Bollensis, &c. According to Voltz, it isa “ pen” analogous to that 
of Loligo Bollensis. According to Mantell and Quenstedt, it is a broad 
dorsal plate, more or less corneous in the middle, and with two 
strong calcified “asymptotic bands.”’ Prof. Huxley is now enabled 
* In the Collections of the Rev. J. Montefiore, Mr, Henry Norris, sen., and 
Mr. Day, and in the British Museum. 
F 2 
