INDIAN CYPRINID^. 



241 



necessary to recollect that the herbivorous Cyprins are characterised by their 

 plain colours and great length of intestinal canal, which varies from six to 

 twelve lengths of the body in the different groups ; those with the shortest 

 (the Barbels) intestine being in the centre of the sub-family, it follows that 

 the two extremes must meet, or shew a tendency to approximate or close. 

 The herbivorous Carps are united to the Sarcohorince by means of the 

 Gonorhynchs and Systoms, and shew like the last a tendency to form a circle 

 of themselves, though it is probable that the group is yet far from being- 

 complete. The Sarcohorince and the Loaches are united by two new types, 

 the Platycara and Psilorhynchus ; and the Schistura in additioft to approxima- 

 ting to the Platycara unites, or shews a tendency to unite both in form and 

 habits with the PceonomincB, the group with which we set out ; thus exempli- 

 fying the first principle of natural classification, namely, that every natural 

 series of beings in its progress from a given point, either actually returns, 

 or evinces a tendency to return again to that point, thereby forming a 

 circle.* 



41. The second test of a natural group relates to the number of its 

 types. On this point there exists some difference of opinion among 

 writers on the natural system, which their profound inquiries are now 

 doing much to remove. It is a question which, to understand sufficiently 

 for practical purposes, requires an extensive knowledge of natural history, 

 and a mind somewhat more imbued with the spirit of philosophy than has 

 hitherto been considered requisite in those who ventured to name new 

 genera. It has already been said that the lower jaw of the Labeos agrees 

 with that of the Cirrhins, in being formed of two bones articulated behind 

 to the anterior process of the preoperculum, and that in front a transverse 



* Swain. Nat. Class, and Geog. Dist. Anini. 224. 



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