BE'LEMNITES (Gr. belemnon, a dart or arrow), an interesting genus of fossil cepha lopodous mollusea, the type of a family called to the whole of which the name B. is very generally extended, closely allied to the sepiacle, or cuttle (q.v.) family. No recent species of B. is known: fossil species are very numerous, and are found in all the oolitic and cretaceous strata, from the lowest liar to the upper chalk, some of which are filled with myriads of their remains. These remains are generally those of the shell alone, which is now known to have been an internal shell, entirely included within the body of the animal, like that of the cattle. The shell, as seen in the most perfect speci mens, is double, consisting of a conical chambered portion (the phragmocont), inserted into a longer, solid, somewhat conical or tapering, and pointed sheath. The space between the phragmocone and sheath is occupied either with radiating fibers or conical layers. The chambers of the shell are connected by a tube (siphunele), so that the animal probably had the power of ascending and descending rapidly in the water. Its arms are
known, from some singularly perfect specimens, to have been furnished with horny hooks; and these it probably fixed upon a fish, and descended with its prey to the bot tom, like the hooked calamary (q.v.) of the present seas. Remains of an ink-bag, like that of the cuttle, have been found in the last and largest chambers of the B.; but remains of this chamber. which must have contained all the viscera of the animal, are very rarely preserved, having been very thin at this part. The part most coin moldy found, and generally known by the name of belemnite, is the solid mum, or point into which the sheath was prolonged behind the chambered shell. These have received such popular names as arrowheads, petrified fingers, .specter-candles, picks, thunder stones, etc., from their form, or from the notions entertained of their nature and origin. B. appear to have been of very different sizes; in some of the largest, the mere macro is 10 in. long, and the entire animal, with its arms outstretched, must have been several feet in length