39 



"secundum principia Naturae et Artis", and states in an- 

 other place that u classis ac ordo" are the work "Natu- 

 rae et Artis". Both of the writers, however, were per- 

 fectly convinced that some definite system was an in- 

 dispensable requisite, a "filum ariadneum — sine 



quo chaos", and to both of them belongs the honour 

 of having, each in his own department of science, estab- 

 lished that essential system. 



The three remaining parts of Artedi's "Ichthyologia" 

 constitute, as Linnaeus remarks in the Introduction, the 

 practical application of the theories put forward in 

 what preceded. The first of them is entitled "Genera 

 Piscium", and contains a presentment of the System of 

 Fishes as it was conceived by Artedi. The Class of 

 Fishes he divided into 5 Orders, one of which, however, 

 the "Plagiuri (with horizontal caudal fin)", embraced 

 the whales. Though Artedi on several occasions pointed 

 out that whales in many particulars resembled Mam- 

 mals, he did not seem able, any more than his pre- 

 decessors, to decide upon excluding them from the class 

 of Fishes. It was not until Linnaeus published the tenth 

 edition of his "Systema Naturae", 20 years later, that 

 they were once for all banished from the Glass to which 

 they have no just claim to belong. The other four Or- 

 ders in Artedi's System are: — Malacopterygii, the soft- 

 rayed fishes, Acanthopterygii, the spiny-rayed osseous 

 fishes, Branchiostegii, osseous fishes but lacking bones 

 in the gills, and Chondropterygii, real cartilaginous fishes, 

 embracing also sturgeons and lampreys. This classifi- 

 cation is marred by numerous shortcomings, as was 

 only to be expected considering it was a first attempt. 

 When sturgeons and lampreys, however, are removed 

 from the last-named Order, the Chondropterygians form 

 a unitary conception, and they still go under the same 

 name to this day. The Branchiostegals, on the other 

 hand, formed an entirely artificial group, and were soon 

 disintegrated as such, the several members being rele- 

 gated to other places in later Systems. The remaining 

 two, again, the Acanthopterygians and the Malacoptery- 



