430 Reviews — Kners Classification of the Ganoids 



statement, that before him, that excellent ichthyologist, Mr. Bleeker, 

 had promulgated similar ideas about the dispersing of the Ganoids, 

 cannot be accepted ; for, with the exception of the Sturgeons and the 

 Cephalaspids, Mr. Bleeker retains all the other commonly so termed 

 Ganoids together as a special class under the common name of 

 •' Ganolepides," and for his subdivisions ("orders") he creates new- 

 names, such as Ganoscomheresoces, Ganoclwpceoids, Ganocharicini, Gano- 

 sauri, etc. We must not charge the author with regarding these 

 forms as the ancestors or prototypes of the recent Scomheresoces, 

 Char acini, Clupece, Sauri (or Sauris'f). 



No doubt the idea of a Ganoid has hitherto been rather vague and 

 undefined; many of the first anatomists, zoologists, and palaeonto- 

 logists have endeavoured in vain to give to this order more definite 

 limits and an established base. But if there be any truth in Prof. 

 Kner's views, that Ganoids are only the progenitors of the Teleostei, 

 the immediate ancestors and prototypes of the Acanthopteri, Physos- 

 tomi, etc., families of the recent ichthyological system, then they 

 must be a somewhat heterogeneous assemblage of forms, showing 

 but feeble marks of affinity towards each other, and passing insen- 

 sibly into the most different types of the actual epoch. Is this the 

 answer that the synthetic method would give us, when applied to the 

 present question? I mean that method which, giving up all pre- 

 conceived ideas, patiently putting genus to genus, until families are 

 formed, and family to family after their natural affinities, until the 

 whole systematic building stands before us ? Confiding upon a 

 careful perusal of all the more important publications of the last 

 thirty years on palgeichthyology, I venture to give a negative answer 

 to this question. It is my intention shortly to treat this subject 

 more fully. But, in the mean time, I will just state what I believe 

 to be the chief results of the scientific labours bestowed upon that 

 important question, — the systematic arrangement and limitation of 

 Ganoids, — that others who have also studied this subject may have 

 an opportunity of comparing my humble thoughts on the subject 

 with their own results. 



The Ganoids form three great divisions or series : — 

 A. LepidosteidcB, composing all the genera that through their 

 armour of rhombiferous ganoid scales, position of the ventrals, 

 structure of the paired fin, fulcral scales on the fin-borders, presence 

 of true branchiostegal rays, etc., are related to the recent Lepidostei. 

 I know of no satisfactory division of this series ; that which I 

 should most recommend is the old division into Heterocerci and 

 Homocerci ; also taking into account the very different size of the 

 scales. For instance Cheirolepis ^ is microlepidote and heterocercal ; 

 Sauropsis, microlepidote and homocercal ; Palceonisciis, macrolepi- 

 dote and heterocercal ; Lepidotus, macrolepidote and homocercal. 

 But it is very doubtful if any definite limit of demarcation can be 

 drawn between smaller and larger scales, and between heterocercal 

 and sub-homocercal caudal fins, and still more so, if such limits 



^ Professor Young's discovery of the "jugular plates" of this genus, has made its 

 poistion somewhat doubtful. 



