24 • BOARD OF AGRICULTURE. 



B. — Fish with fins having cartilaginous rays hardly distinct from 

 a membrane. 



'42. Petromyzon, Lamper Eel. 



43. Acipenser, Sturgeon. 



44. Squalus, Sharks. 

 r45. Raja, Skates. 



Class II. — Fish having tails placed horizontally, including whales. 



Chondropterygii, cartilaginous or leath- 

 ery fins. 



We have thus given the system of Artedi in detail, because, 

 although Willoughby and Ray, by their improvements in classifica- 

 tion of this branch of natural history gave it a more respectable 

 position among the sciences than it before had, Artedi placed it on 

 a firm basis and gave permanency to its nomenclature. 



Other writers on this subject followed from time to time and 

 added, by their researches and discoveries, to the fund of knowledge 

 on these matters. Among them, Klein published an interesting 

 work in 1740, on the "Natural History of Fishes," in which he 

 endeavored to improve upon Artedi. 



He increased the number of genera partly from the number of 

 newly discovered fishes till then undescribed. He divided them 

 into three grand orders, viz : 



I. — Cetaceous or whales. 

 II. — Fishes with concealed gills as in Lamprey Eels. 

 III. — Fishes with open gills. These were again separated into 

 many sub-divisions or groups, and then again into genera. 



Artedi's arrangement, however, continued to take the lead until 

 1766, when Linneus himself, who at first had adopted his friend 

 Artedi's system, came out with a new one of his own, which then, 

 from the popularity of its author as well as from its simplicity, 

 kept the ascendancy for several years. 



Linneus' System. 

 Order I. — Apodes — fishes having no ventral fins. 

 Order II. — Jugulares — fishes having their ventral fins placed 



before or forward of the thoracic or pectoral fins. 

 Order III.— TnoRAcici — fishes having the ventral fins placed 



directly below the pectorals. 

 Order IV.^ — Abdominales — fishes having their ventrals placed 



behind the pectorals. 



This was a very simple and concise arrangement, but neverthe- 

 less a purely artificial one, and by following it out fishes of very 



