Mr. J. McClelland on Indian Cyprinidae. Ill 



pria, or true Loaches, it is almost cylindrical, and generally 

 very long. Some of the Schistura are possessed of an air- 

 vessel, placed as usual in the upper part of the abdomen, of 

 an oval shape, and divided into two lateral cells by a longitu- 

 dinal septum ; but in Cobitis prop., or Loaches with entire 

 caudal, I have not found any trace of that organ in the ordi- 

 nary position : but in different species that I have dissected, 

 it is placed in a small bony case over the entrance to the ceso- 

 phagus ; this case consists of a single subglobular cell, al- 

 though in the European species it has been found to be bilo- 

 bate. In those Schisturce, on the other hand, which are with- 

 out the abdominal natatory bladder, I find the organ situated 

 over the entrance to the oesophagus, as in Cobitis prop., but 

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

 termediate tube. 



28. Having thus explained the general principles on which 

 I have subdivided 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 endeavour 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 ana- 

 lysis of the whole class, we can only attempt to form an esti- 

 mate on the subject by comparing Cyprinid<E with what seem 

 to be analogous groups in other classes, to which the philo- 

 sophical 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 po- 

 pular introductions that ought to be universally read, as well 

 as in several jjapers that have been published within these last 

 twenty years in the Transactions of the Linnaian 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 

 Linnajus when he compared ruminating quadrupeds to galli- 

 naceous birds*, both of which evince the greatest intelligence, 

 docility and contentment under the domestication of man." 

 Appendages to the head, whether in the shape of horns, crests, 

 or fleshy protuberances, and the property of affording whole- 



* Such analogies were, as Mr. MacLeay lias shown, known to Aristotle, 

 by whom, however, as well as by all subsequent writers up to the time of 

 Mr. MacLeay himself, they were mistaken for affinities. 



