174 DR. MANTELL ON BELExMNITES, ETC. 
The outline, Plate XIV. fig. 1, is intended to convey an idea of the form of the 
animal of the Belemnoteuthis, so far as the fossils hitherto discovered warrant the 
restoration ; of course this sketch is only approximative, and is given as a mere 
diagram of what is actually Imown as to the shape and structure of the original, and 
not as an accurate delineation of the living animal ; for there are strong reasons to 
conclude that the phragmocone was wholly internal, or at least was covered by the 
skin. The above is, I believe, a correct description of the Belemnoteuthis, and of the 
form and relations of the several parts of its structure: it is based on the specimens 
described and figured by Mr. Channing Pearce, Professor Owen*, and Mr. Cun- 
NiNGTON'f', and others in my possession. 
Now in order to connect the body of the Cephalopod above described with the 
elongated conical fossil commonly known as the Belemnite, and termed by natural- 
ists the guard or osselet of the same, it has been assumed that the terminal chambered 
cone of the former (Plate XIII. figs. 2, 3, 5) was originally implanted in the alveolus 
or cavity of the latter; like the unquestionable phragmocone of a Belemnite, repre- 
sented in Plate XV. figs. 4, 5, a, a. It follows, if we admit the correctness of this 
interpretation, that every example of the chambered conical shell of a Cephalopod, 
found in the Oxford Clay, is the phragmocone of a Belemnite that has slipped out of 
the alveolus of the guard, and been compressed into its present shape by the weight 
of the superincumbent strata. Upon the correctness of this supposition the generic 
identity of the Belemnoteuthis and the Belemnite entirely rests; for no specimen has 
yet been met with, in which the guard of a Belemnite is in natural contact with 
the muscular mantle, and other soft parts. If the phragmocone of the Belemnite, 
and the chambered shell of the Belemnoteuthis be not identical, then we know 
nothing whatever,/rom actual observation, of the soft parts of the animal to which 
the Belemnite belonged : to this point therefore I would first solicit particular atten- 
tion. 
Phragmocone of the Belemnoteuthis . — As the figures in the Philosophical Transac- 
tions, 1844, Plate III., &c., and in the London Geological Journal, Plate XV. XVI., 
show the phragmocone in natural connection with the muscular tunic or mantle, &c., 
I need not adduce further examples of this undisputed fact, and will therefore only 
remark, that such specimens are of rare occurrence : in most instances, the detached 
chambered shell, more or less flattened, is found imbedded in the clay, with but few, 
if any, vestiges of the soft parts, as in Plate XIII. figs. 1,2, 3, 5. In this state, these 
fossils occurred by hundreds on the newly-exposed surface of the Oxford Clay near 
Trowbridge. My son describes some areas when first laid bare by his labourers, as 
being literally spangled over with the nacreous cones of Belemnoteuthes, and the 
splendid iridescent shells of Ammonites ; while here and there Belemnites of large 
size, with their phragmocones attached, were lying in relief. Upon drying, the thin 
* Philosophical Transactions, 1844, p. 77-80, Plates III. IV. V. VI. 
t London Geological Journal, Plates XV. XVI. 
