PISCES—LAMPREY. 721 
fishery was but little attended to, it may be conjectured, that their age is 
still more considerable. 
SUB-CLASS I.—GARTILAGINOUS FISHES. 
Tue bones of the fishes of this division are essentially cartilaginous, and, 
in general, are never formed of bony fibres. The most general character 
common to the cartilaginous fishes, and sufficient to distinguish them from 
all others, is that of wanting entirely, or having only in a rudimentary form, 
the maxillary and intermaxillary bones, the place of which is supplied by 
bones analogous to the palatine ones. 
ORDER I.—CYCLOSTOMI. 
Fisues of this order have the jaw fixed in an immoveable ring; bronchi 
fixed, and the openings numerous. 
THE LAMP BEY.2 
Tue lamprey much resembles the eel in its general appearance, butis of a 
-ighter color, and rather a clumsier make. It differs, however, in the 
mouth, which is round, and placed rather obliquely below the end of the 
nose. It more resembles the mouth of a leech than an eel; and the animal 
has a hole on the top of the head, through which it spouts water, like the 
cetacea. There are seven holes on each side for respiration; and the 
fins are formed rather by a lengthening out of the skin, than any set of 
bones or spines for that purpose. As the mouth is formed resembling that 
of a leech, so it has a property resembling that animal, of sticking clase to, 
and sucking any body it is applied to. It is extraordinary, the power they 
have of adhering to stones ; which they do so firmly, as not to be drawn off 
without some difficulty. We are told of one that weighed but three pounds 
and yet it stuck so firmly to a stone of twelve pounds, that it remainea 
suspended at its mouth; from which it was separated with no small diffi- 
culty. As to the intestines of the lamprey, it seems to have but one great 
bowel, running from the mouth to the vent, narrow at both ends, and wide 
in the middle. 
1The genus Petromyzon has the maxillary ring armed with strong teeth; lips formed 
for suction ; tongue with two rows of small teeth; a dorsal fin before, and another behind 
the anus. 
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