CEPHALOPODA, 
15 
In others, the Orthoceratites*, it is altogether straight. It is 
not improbable that the animals belonging to these shells, resem- 
bled that of Nautilus or of the Spirula. The 
Belemnites 
Pi’obably belong also to this family, but it is impossible to ascertain 
the fact, as they are only found among fossils ; every thing, hoAvever, 
proves them to have been internal shells ; thin and double, that is, 
composed of two cones united at the liase, the inner one much shorter 
than the other, and divided into chambers by parallel septa, which are 
concave on the side next to the base, A siphon extends from the 
summit of the external cone to that of the internal one, and continues 
thence, sometimes along the margin of the septa and sometimes 
throAigh their centre. The interval between the tAvo testaceous cones 
is filled Avith a solid substance, in some composed of radiating fibres, 
and in others, of self-iiiAmlving conical layers, the base of each being 
on the margin of one of the septa of the inner cone. Sometimes Ave 
only find this solid portion, and at another Ave also find the nuclei of 
the chambers of the inner cone, or Avhat are termed the honeycomb 
cells. Most commonly these nuclei and the chambers themselves 
have left no other traces than some projecting circles on the inside of 
the internal cone. In other specimens again Ave find more or feAver 
of the nuclei, and still in piles, but detached from the double conical 
sheath that enveloped them. 
Of all fossils the Belemnites are the most abundant, 23articularly in 
chalk and compact limestone. f 
M. de Blainville divides them according to the greater or less depth 
to Avhich the internal cone or chambered portion jjenetrates, or as the 
edges of the external cone have a small fissure or not, or as the exter- 
nal surface is marked on one side by a longitudinal furroAV, or by tAvo 
or more furroAvs tOAvards the summit, or finally as that surface is 
smooth and AA'ithout furroAA^s. 
Bodies A'ery similar to Belemnites, but Avithout a caA'ity and Avith 
a rather prominent base, form the genus nctinocamax of Miller. (a) It 
* Breyn. de Polythal., pi. iii, iv, v, and vi. ; and Waleh, Petrif. of Knorr., Supp. 
IV, 1), iv, d, iv. See also Sage, Journ. de Phys. an. IX, pi. 1, nnder the name of 
Belemnite. 
The best works on this singular genus of Fossils, are the Memoires sur les 
Belemnites consideries soologiquemenf el geoloyiqttemenf, by M. de Blainville, Paris, 
{j:^ CaJ Mr. Miller gives the following description of the genus Actinocamax 
which he has established and separated from the Belemnites. 
Gen. Char. A club-shaped Spathose concretion, consisting of two nearly equal, 
longitudinal adhering portions. Apex pointed : base a convex, but obtuse cone. 
The whole formedof a series of enA'eloping fibrous laminae. 
Specific character. Act. verus. A club-shaped Spathose semi-transparent horn 
coloured concretion ; base convex, obtuse, conical ; apex submamillar. Sides de- 
pressed towards the lower end, showing two longitudinal, towards the apex branch- 
ing, impressions of blood vessels. 
The species was found in the Chalk Strata in Kent, Wiltshire, and Sussex, in the 
strata which contain marine animals, so that Mr. Miller does not hesitate to consider 
it as an inhabitant of the sea. — Exg. Ed. 
