226 TWO DIVISIONS OF TRACHELIPODS. 



great sections, viz. herbivorous and carnivorous ; the carni- 

 vorous are also divisible into two families of different office,, 

 the one attacking and destroying living bodies, the other 

 eating dead bodies that have perished in the course of na- 

 ture, or from accidental causes ; after the manner of those 

 species of predaceous beasts and birds, e. g. the Hya3nas and 

 Vultures, which, by preference, live on carrion. The same 

 principle of economy in nature, which causes the dead car- 

 casses of the hosts of terrestrial herbivorous animals to be 

 accelerated in their decomposition, by forming the food of 

 numerous carnivora, appears also to have been apphed to 

 the submarine inhabitants of the most ancient, as well as of 

 the existing seas; thus converting the death of one tribe into 

 the nutriment and support of hfe in others. 



ft is stated by Mr. Dillvvyn, in a paper read before the 

 Royal Society, June 1823, that Pliny has remarked that the 

 animal which was supposed to yield the Tyrean die, obtained 

 its food by boring into other shells by means of an elon- 

 gated tongue ; and Lamarck says, that all those Mollusks 

 whose shells have a notch or canal at the base of their aper- 

 ture, are furnished with a similar power of boring, by means 

 of a retractile proboscis.* In his arrangement of inverte- 



the manner in which they have the principal viscera packed v^ithin the spiral 

 shell. 



* The proboscis, by means of which these animals are enabled to drill 

 holes through shells, is armed with a number of minute teeth, set like 

 the teeth of a file, upon a retractile membrane, which the animal is en- 

 abled to fix in a position adapted for boring or filing a hole from without, 

 through the substance of shells, and tlirough this hole to extract and feed 

 upon the juices of the body witliin them. A familiar example of this or- 

 gan may be seen in the retractile proboscis of Buccinum Lapillus, and 

 Buccinum Undatum, the common whelks of our own shores. A valuable 

 Paper on this subject has recently been published by Mr. Osier (Phil. 

 Trans., 1832, Part 2, P. 497,) in which he gives an engraved figure of 

 the tongue of the Buccinum Undatum, covered with its rasp, whereby it 

 perforates the shells of animals destined to become its prey. Mr. Osier 

 modifies the rule or the distinction between the shells of carnivora and 

 hcrbivora, by showing that, although it is true that all heaked shells in- 



