32 BELEMNITES.— NUMMULITES, &c. 



anterior to the creation of nearly all the mammals ; they vary 

 much in form, and still more in size ; some are not larger than a 

 bean, and others are more than four feet in diameter. More than 

 three hundred species of them are known, and they are divided 

 into several genera, according to the manner in which the shell is 

 rolled, the position of the syphon, the form of the partitions, &c. 



27. We give the name of Belemnites (from the Greek belem- 

 non, a dart) to other fossils, which also seem to have belonged to 

 the cephalopods, but which, in place of being an external shell, 

 must have been lodged in the interior of the animal, like the bone 

 of the cuttle-fish. They are conical in form, and are chiefly 

 composed of a series of little horns, fitting one in the other like 

 boxes in a nest, traversed by a syphon and terminated anteriorly 

 by a horny plate that forms a sort of chamber, in the interior of 

 which we som.etimes find the remains of an ink-bag, similar to 

 the sack which fulfils the same purposes in the naked cephalo- 

 pods. The belemnites are not met with in strata as old as the 

 ammonites ; but they abound in the middle and upper layers of 

 the secondary formation, and cease to exist in the upper layers 

 of the chalk. 



Until lately, a host of microscopic shells of lenticular form and 

 without apparent opening, designated by authors under the names 

 of NUMMULITES (from the Latin numma, a piece of money), 

 CAMERiNEs (from the Latin camera, chamber), foraminifera 

 (from the Latin fo?'amen, a hole, and fcro, I bear), &c., were 

 referred to the order of cephalopods ; these little bodies abound 

 to such an extent in certain soils, that they of themselves exclu- 

 sively constitute chains of hills and immense banks of building 

 stone ; but they are also found in European seas, and, on observ- 

 ing them when alive, we are convinced that the animals to which 

 they belong do not resemble either the cephalopods or even the 

 mollusks, in anything : they are beings of ^a very peculiar struc- 

 ture, and seem more to approximate the polypi. 



27. What are belemnites ? What are their characters ? Where are they 

 found ? 



