THE STURGEON FAMIL Y 35 



in the oldest, and therefore the first, sub-class of the class 

 of Fishes. 



The Sturgeon Family includes two genera only, whereof 

 the first, tAcipenser, consists of about twenty species, all bearing 

 a remarkable resemblance to each other, and comprising the 

 largest fresh-water fish of the Northern Hemisphere. The 

 body is much elongated and nearly cylindrical ; the skin is 

 protected by ridged bony plates or " scutes," arranged in five 

 longitudinal rows, one along the back, two along the upper 

 region of the sides, and two along the lower or ventral region. 

 The sharply-angled keels or ridges of these plates give the fish 

 a strangely antique appearance, and suggest a pentagonal form 

 of body. The interval between the plates is covered with small 

 bony scales. The skull and framework of the head is cartilagi- 

 nous or gristly, well protected by external bony armour ; the 

 entire skeleton also is gristly, and the vertebral column is 

 prolonged so as to support the upper and longer lobe of the 

 caudal fin. 



The snout projects far beyond the mouth, which is very 

 small relatively to the size of the fish, toothless, transverse, 

 with thick lips capable of protrusion like a short trunk. Be- 

 tween the tip of the snout and the mouth hang four fleshy 

 barbules or wattles, arranged in a straight transverse row. The 

 arrangement of the fins corresponds to that usual in Teleostean 

 fishes, subject, however, to some modification in position. Thus 

 the dorsal is set very far back, close to the tail fin, the anal fin 

 being opposite but slightly in rear of the dorsal. The pectoral 

 fins are set low, at the side of the throat, and are long and 

 powerful ; the ventral fins are placed far back, just in front 

 of the vent. 



The Sturgeons are built on a scale suggestive of destructive 

 habits and formidable rapacity ; but there exist, in truth, no 

 more inoffensive creatures. Like that of the whales, the diet 

 of the sturgeon consists of lowly organisms which nobody 

 misses, and the fish is incapable of inflicting injury on man. 



