CLASS Y. PISCES: ORDER 2. GANOIDEA. 431 



the wing-like form of the pectoral tins. It is three to five feet long; has a stino- measurino- three 

 or four inches, and is found in the European seas ; common in the Mediterranean. 



Genus CEPHALOPTERA : Cephuloptera. — To this belongs the Sea Devil, or Ocean Vam- 

 pire, C. vampirus, sixteen to eighteen feet long, and eighteen feet wide, and occasionally weio-hs 

 three or four tons. It seizes the cables of small vessels, and sometimes drags them along with 

 great swiftness for several miles. Found on our southern coasts. 



ORDER 2. GANOIDEA. 



The term Ganoidea is derived from the Greek r/anos, splendor, and v/as applied by Agassiz to 

 a large number of fishes, mostly fossil, distinguished by the angular form of the scales, these bein<r 

 composed of corneous or osseous substances, disposed one upon the other, and covered by a thick 

 coat of enamel, and consequently resembling teeth. As a system more convenient for our pur- 

 pose we adopt the classification of Miiller, applied to the living groups and divided into the Chon- 

 drostca, having a cartilaginous skeleton, and the Holostea, having a bony skeleton. 



THE CIIOXDEOSTEA. 



Of these there are many fossil species, but of the living there are only two families, the 

 Acipenscridce and the Spatularidce. 



Ge7ius ACIPEXSER : Acipenser, includes several species of Sturgeon ; these have an elongated 



body, and a funnel-shaped and 

 protrusible m o u t h , without 

 teeth, jdaced on the under side 

 of the head. 



The Common Sturgeon of 



THE COMMON STURGEON. EUROPE, A. StUVtO, IS frOlll SIX 



to twelve feet long ; one weigh- 

 ing four hundred pounds is mentioned by Pennant. It is found in the European seas and rivers, 

 especially in the north ; its flesh is delicate and is compared to veal. Henry I., of England, 

 declared it to be a royal fish and forbade it to be eaten at any table but his own. 



The Beluga, A. huso, attains the length of fifteen feet, and weighs from one to three thou- 

 sand pounds. Its flesh is not greatly esteemed, but from its air-bladder an abundant supply of 

 isinglass is obtained, in the Russian rivers, and also in the Caspian and Black Seas, where this 

 fish is common. Other species, taken in large numbers in these regions, are the Sterlet, A. 

 ruthenus, and the Scherg, A. helops. From the female roe of all these species of sturgeons, a 

 substance called caviare is obtained, forming an important article of commerce in the countries 

 around the Mediterranean. As a hundred thousand of the beluga alone are said to be annually 

 taken in the Russian rivers, and as the roe constitutes often one-third of tlie whole weight of 

 this fish, the extent of this trade may be easily calculated. 



The Siiort-nosed Sturgeon, A. brevirostris, found occasionally in the Hudson and other 

 American rivers, iesembles the European sturgeon, and may possibly be of the same species. 



The Lake Sturgeon, A. rubicundus, four to six feet long, is found in lakes Ontario and Erie, 

 and in the Ohio River. 



The Sharp-nosed Sturgeon, A. oxyrhynchus, is seven to eight feet long, and is found in the 

 American Atlantic rivers. Other species are found in the northern and northwestern rivers of 

 North America. 



Genus SPATULARI A : Spatularia, Includes certain species found in the great rivers of North 

 America, of Avhich the Paddle-Fish, S. folium, of the Mississippi, is the type. In these the skin 

 is naked and the nose prolonged into a thin leaf-like appendage, sometimes nearly as long as the 

 body. 



THE HOLOSTEA. 



This group includes several families most of which are fossil : of the Amiidce, which are clothed 

 with small horny scales, usually covered with a layer of enamel, the Amia marmorata is the best 



