THE COMMON BRITISH STURGEON. 

 G AN 01 DEI. 



THE COMMON BRITISH STURGEON. 



Acipenser Thompson*, BALL, Thompson's Nat. Hist, of Ireland, iii. 245. 

 ,, sturio, Common Sturgeon, PENN. Brit. Zool. iii. 164, pi. 22. 



,, ,, ,, DONOV. Brit. Fish. pi. 55. 



,, ,, ,, ,, JENYNS, Man. 493. 



,, ,, Sturgeon, FLEM. Brit. Anim. 173. 



AciPENSERiDJ3. Family Characters. Form elongated, pentagonal ; the 

 angles of the body formed by the crests of five longitudinal rows of bony 

 shields ; mouth on the ventral aspect, protractile, toothless ; no branchio" 

 stegals ; internal skeleton cartilaginous, except the basal cephalic plate of 

 bone, which extends backwards under the first five dorsal vertebras ; vertical 

 fins supported anteriorly by short bony rays ; a long spiral intestinal valve ; 

 pancreas glandular. 



ACIPENSER. Generic Characters. Snout tapering, beak-shaped, with four 

 barbels depending from its ventral surface before the mouth ; an accessory 

 gill, and, at the upper border of the gill-cover, a spout-hole ; trunk of the 

 tail not flattened. HecJcel. 



THE STURGEONS are Ganoid fishes of a lengthened 

 shape, having a cartilaginous skeleton, and the protractile 

 mouth situated under the eyes on the ventral surface 

 considerably behind the tip of the snout. The jaws are 

 much more protractile than those of a Shark, and consist 

 of the premaxillaries going round the upper or anterior 

 border of the mouth, with small maxillaries articulated 

 to them laterally and connected also to the palatines. 

 The mandible is formed principally of a pair of bony 

 limbs, united to each other at the symphysis, ending late- 



