FISHES. 359 



But the greatest number of these is found in the family of the 

 scombres ; the cods have many of them ; other fishes, as those of the' 

 labrus, silurus, cyprins, and pike, are entirely destitute of them ; 

 others, as the perches and pleuronectes liave them short, and very 

 small in number ; river perches have only three, the pleuronectes onlv 

 two ; in the sturgeon they are numerous, but still short and united 

 by vessels and cellular tissue, in a mass Avhich constitutes just a shade 

 of difference between their usual state of freedom, and the compact 

 pancreas of the rays and the genus squalus. In the sturgeon each of 

 these appendices has a communication by means of an appropriate 

 orifice with the canal. In the rays and squalus, as in the quadrupeds, 

 the i)ancreas is a true conglomerated gland, which secretes its fluid 

 by a common canal. 



The anus has sonic very singular varieties in its position, and does 

 not depend upon that of the ventral fins in this respect; still it is 

 always situated more behind than tliese fins, but when they are under 

 the throat or when absent, the anus is itself supported frequently 

 beneath the throat : it is never behind, farther than the base of the tail, 

 while the abdominal cavity is often prolonged into one or two sinuses 

 on the ridges of the tail behind the anus. 



To give a particular example of the arrangements of the alimen- 

 tary canal, we shall mention that in the perch, it consists of an oeso- 

 phagus (A), which is short, of the form of a siphon, which opens im- 

 mediately into a stomach (5), formed like an obtuse bottomed sac. 

 Internally, the oesophagus has dense wrinkles covered with very fine 

 velvet, and which, in the stomach, are changed into larger wrinkles; 

 these are salient, irregular and folded across, and amount in number 

 to seven or eight ; from the right side of the stomach towards the 

 middle of its height a short branch is given off (C) of the same 

 nature as the stomach itself, but much more narrow and with 

 wrinkles only amounting to four or five. 



It is at the extremity of this little branch that we find the jjylorus, 

 Avhich is a very delicate constriction, and below it is the velvet sur- 

 face which is prolonged into a sort of annular little valve, thin and 

 indented at its margin, and it prevents the return of the food from 

 the intestine to the stomach. 



Around the origin of the intestine, three blind guts or coecal appen- 

 dages (Z), D, £>,) adhere ; they are much thinner, and a little longer 

 than the branch of the stomafth which they surround. 



They communicate with the intestine by many little orifices situa- 

 ted behind the little valve of the pylorus. Their internal membrane 

 is stuck with little fringes, or Avith small narrow and acute slips, the 

 bases of which adhere to one another, and form a sort of net- work ; it 

 oozes out a very copious mucous secretion. 



The intestine forms two folds, which proceed at first behind along 

 the left side, (£, £,) as far as the middle of the abdomen, returning 

 suddenly towards the stomach by (i^, i^), and then taking a curved 

 direction in its course to the anus, it describes an oblique line, ((r). 



some other fishes, is a sort of salivary gland ; and it is only in fishes destitute of 

 pyloric appendages that he has found this substance. 



