IS 



elongation ; but when in a state of contraction, they 

 are thrown into folds, in such a manner, that portions 

 of the same vessel are parallel to each other. This 

 necessarily arises from the particular manner by 

 which they are attached to the adjacent parts by mem- 

 brane. The same particularity of the blood vessels 

 must be common to the snail, the leach, and to all 

 animals that have the power of increasing and dimi- 

 nishing themselves in length. 



The aesophagus extends in a direct line, to the 

 stomach, which is about three-fourths of an inch. 

 The stomach is near the size of a small pea of an irre- 

 gular, oval form. Its external surface appears mus- 

 cular, and its internal membranous. It generally 

 contains earth, which is its common and natural food. 

 The intestines commence at the stomach, and continue 

 to the extremity of the tail; they lie in a convoluted 

 form, when the animal is in a state of contraction ; but 

 are united by membrane in such a peculiar man- 

 ner to the adjacent parts, as to form a straight canal, 

 from the commencement of the aesophagus, to the 

 extremity of the tail, when in a state of elongation. 



Spallanzani,* in speaking of the barbel, says " the 

 " conformation of the barbel does not correspond 

 *' with the carp, and various other fishes. The seso- 

 " phagus, stomach, and intestines, constitute a single 



* Dissertation iii. Sec. cxxxii. 



