LECTURE X. 129 



found in considerable quantities, cast on the 

 shores, and forms a small article of commerce, 

 being used for various purposes by different arti- 

 ficers. It also serves, when reduced to powder, as 

 a good common dentifrice, and is indeed con- 

 sidered as one of the most innocent that can be 

 used for that purpose. 



The anatomy of the Cuttle-Fish is highly 

 curious, and has long ago been detailed by Swam- 

 merdam and others ; and was even not unknown 

 to the ancients. The animal is furnished with a 

 pair of large lungs or respiratory organs, situated 

 nearly as in quadrupeds, but they are constituted 

 on a different principle, and are more allied to the 

 gills of Fishes. The most striking particularity 

 however in this animal is that of having three dis- 

 tinct hearts : these are situated in the form of a 

 triangle, and the lowest of the three is larger than 

 the rest. The eyes, which in this whole genus are 

 remarkably large, are covered, as in Eels and some 

 other fishes, by the common skin, which is trans- 

 parent in those parts. The pupil of the eye appears 

 double, and the internal cavity of the eye is lined 

 with a purplish-coloured mucus, which causes the 

 eyes of the living animal to appear phosphoric or 



LECT. II, K 



