150 
ACIPENSEE, 
The mouth under the snout, without teeth, the jaws capable of 
being drawn within the cavity. Barbs generally four, about midway 
between the mouth and snout. Nostrils in front of the eyes; spiracles 
behind the eyes; a single opening to the gills, covered with a 
moveable oper '.ulum. The tail with unequal lobes, and the vcrtebriB 
continued aiuug the upper lobe as in Sharks. 
STURGEONS. 
With a general likeness to tke form of tke Sharks, there 
are in this genus some remarkable departures from it, which 
shew a greater variation from that type, and a nearer approach 
to the bony class of fishes, than are seen in any other of the 
plagiostomes or cartilaginous tribes, in some particulars even 
amounting to a positive contrast. We may conclude also that 
the difference is equally great in the internal and less-observed 
organization, especially of the brain, which is of small size, 
and the nervous system in general; for their instinctive dis- 
position of timidity and the absence of violent appetites are 
more distinctly marks of variation, than the particulars to be 
pointed out of their merely external shape. 
The head of the Sturgeons is lengthened into a snout, which 
is slightly turned up; and the mouth is placed far beneath, 
with sensitive tendrils about midway between the mouth and 
snout. There is a spiracle behind each eye, by which 
a current of water is supplied to the gills, when, as must 
often happen from the manner in which they seek their food, 
the necessary supply cannot be obtained through the mouth. 
But at this point the resemblance to the family of Sharks 
becomes interrupted by the feebleness of the jaws, and the 
entire want of teeth; and in place of a formidable arrangement 
of offensive arms, as in that order, the lips are soft and fleshy, 
with, in the case of the Coimnon Sturgeon, separate lobes, 
that from the nerves distributed to them we judge to be 
