234 



INDIAN CYPRINID^. 



longitudinal septum ; but in Cohitis prop, or Loaches with entire caudal, I have 

 not found any trace of that organ in the ordinary position, but in different 

 species that I have dissected, it is placed in a small bony case over the entrance 

 to the oesophagus ; this case consists of a single sub-globular cell, although in 

 the European species it has been found to be bilobate. In those Schistures, 

 on the other hand, which are without the abdominal natatory bladder, I find 

 the organ situated over the entrance to the oesophagus as in Cohitis prop.^ 

 but formed of two small globular cells, joined together by an interme- 

 diate tube. 



28. Having thus explained the general principles on which I have 

 sub-divided the family, it may be useful to examine how far the results 

 are likely to correspond with those laws that have been laid down as the 

 basis of natural classification. With this view, we should first of all en- 

 deavour to ascertain the denomination of the family, or its relation in point 

 of rank to fishes in general ; but as this could only be done after analysis 

 of the whole class, we can only attempt to form an estimate on the subject 

 by comparing Oyprinidce with what seem to be analogous groups in other 

 classes, to which the philosophical views of Mr. Macleay, Mr. Swainson, 

 Mr. Vigors, and other writers on the natural system have been extended. 



29. It might be unnecessary in a communication of this kind, to offer 

 any remarks on the general principles of the natural method of arrangement, 

 as these are fully expounded in popular introductions that ought to be 

 universally read, as well as in several papers that have been published 

 within these last twenty years in the transactions of the Linnsean and other 

 learned Societies. I may however remark, that in addition to those affinities 

 by which animals are immediately connected, there are more remote relations 

 called relations of analogy, by which they typify or represent each other, 

 " a principle which," as Swainson observes, " was in some degree perceived by 



