ZOOLOGY. 33^ 



extreme in excessive differeutiation. Dr. Giiutlier has published an 

 " Introduction to the Study of Fishes," in which he recognizes as orders 

 certain artiticial groups of Teleosts current for a long time; that is, 

 the Acanthopterygii, Acanthopterygii Pharyngognathi, Anacanthini, 

 Physostomi, &c. 



The chaiacters nsed to differentiate these "orders*' fail ui certain 

 representatives referred to each group, and are of really little more 

 systematic importance in several cases than those used to distiuguish 

 the "orders" of Birds. Nevertheless, to each of the "orders" in 

 question are assigned forms which do really differ in important ana- 

 tomical details, and which have far less relation to the types with which 

 they are confoundetl than do the types of the so-called orders exhibit 

 among titemsdccs. We have, consequently, evils here, not only of undue 

 valuation, but also radical defects in appreciation of relationships. 

 But the same author applies a standard as different as possible to the 

 classihcation of the generalized types of Fishes; conuniiting, at the 

 same time, the great mistake of calling those generalized types the 

 highest. All the typical Ganoids, as well as the Polypteroids, and 

 Dipnoans are confused together in one heterogeneous order; all the 

 Chimieroids, and all the Sharks and Kays, are thrown together in a 

 second. There can be no question but that representatives of each of 

 these last two so-called " orders" exhibit far greater diversities in their 

 structure, inter se, than do any of the orders of existing mammals. 

 It is difficult to believe that any consideration could have been given to 

 the principles of taxonomy, or that thought could have been actively 

 involved in such schemes as the last one noticed. 



As to the new orders recently proposed, and to be noticed hereafter, it 

 is probable that the value of the several groups endowed with such rank 

 will be (piestioned l)y the majority of naturalists, and that the types so 

 distiuguished will ultimately be degraded in rank. 



The language of the original from which the abstract is compiled is 

 followed as closely as the case will permit, as the advantages of such a 

 course must be obvious to all on a little retlection. It has however 

 been generally found to be necessary to limit the abstract to the illus- 

 tration of the prominent idea underlying the original memoir, and pass 

 by the proofs and collateral arguments. At the same time it has been 

 often attempted to bring the new discovery into relation with the pre- 

 vions status of information respecting the group under consideration. 

 As to the special discoveries recorded, they have been generally selected 

 (1) on account of the modifications the forms considered force on the 

 system; or (2) for the reason that they are or have been deemed to be 

 of high taxonomic importance; or (o) because the animals _per se are of 

 general interest; or, finally (4), because they are of special interest to 

 the xVmerican naturalist. Of course, zoologists cultivating limited fields 

 of research will find in omissions cause for censure, and may urge that 

 discoveries of inferior importance have been noticed to the exclusion of 



