SALMO. ANALOGIES OF THE SUB-GENERA. 249 



the teeth, as in Anastomus, are small and crowded ; and 

 the lower jaw is even longer than the upper one, although 

 the form of the head is like that of the ordinary salmon. 

 The transition from this type to Coregonus * (Artedi) is 

 beyond dispute. Cuvier, in fact, makes them to follow 

 each other, with the intervention, indeed, of the Corego- 

 nus Thymallus, or the grayling, which he places as a 

 distinct sub-genus; but which we consider the most 

 typical example of the genus from which he has separated 

 it. In this view we only adopt the opinion of Artedi, 

 and, more recently, of Dr. Richardson. Coregonus, then, 

 is composed of the graylings, well distinguished from 

 the true salmon by having a very small mouth, furnished 

 with a few slender teeth, which are altogether wanting 

 in some of the species : the under jaw is always the 

 shortest ; and the gape of the mouth is before, instead of 

 behind the line of the eye : in all other respects the ge- 

 neral structure is completely similar to that of the large- 

 mouthed salmons; so that, having returned to the type 

 we originally commenced with, we may place the whole 

 in a column, and trace the analogical relations of the 

 series to the primary orders. 



ofS\LMO Analogies. Orders of Fishes. 



e„/™„ f Typical, being the most highly or- 7 „ 



balmo. 1 ean j sec j \ ACANTH0PTERYGES - 



Coregonus. Sub-typical. Malacopteryges. 



MaUotus. [ B0 r d [ )nd e e a 8thened; P6Ct ° ral ^JApodes. 

 Anastomus. Mouth very small, opening vertically. Plectognathes. 



Laurida. [ V, ggg£ ' ^^ ^^ '' ^ ^ j C^ilagines. 



If the question was asked, whether Salmo or Coregonus 

 was the most highly organised group, no difference of 

 opinion could possibly arise; because a fish that has all 

 the parts of its mouth well armed with teeth is unques- 

 tionably more perfect, that is, of a superior organisation 

 to one that has few or none of these organs : now, this 

 is just a parallel case with the Acanthopteryges and the 



* This genus was founded by Artedi, — not, as is supposed, by Cuvier. 



