CHAPTER LXI V 
THE LOWEST CLASSES OF VERTEBRATES 
There are a few creatures which, by reason of 
their internal skeletons and jointed back-bones, 
are justly entitled to stand with the vertebrates, 
but yet are lower in the scale than the lowest 
fishes. For these it has been necessary to create 
two grand divisions of the first rank; and they 
stand as two small and very low Classes. It is 
because of their very low position in the zoological 
scale of vertebrates that it becomes important to 
know them. 
THE LAMPREYS. 
Class Marsipobranchii. 
A Lamprey is an aquatic creature which bears 
so strong a resemblance to an eel that for a long 
period all lampreys were regarded as true eels. 
Even to-day, the most important of our species 
is, by unscientific persons, almost universally 
called the “Lamper Eel.” In view of the gen- 
eral external resemblance of these creatures to 
eels of similar size, it is not strange that their true 
character remained for a long period quite un- 
known. As a matter of fact, these creatures for- 
cibly illustrate the unwisdom in animal classifica- 
tion of attaching too much importance to external 
characters. 
The lampreys are the lowest and last creatures 
that have the spinal cord expanded at its upper 
end into a brain, and encased in a skull. But the 
skull is imperfectly developed, and without jaws; 
there is no shoulder girdle, no pelvis, no limbs, no 
ribs, and no paired fins. There is a single median 
nostril, the gills are purse-shaped, the skin is naked 
like that of an eel, and the skeleton is cartilaginous. 
The gills are in the form of a fixed sac, the gill open- 
ings consist of a row of tiny round holes along 
the side of the body, and the mouth is specially 
formed for suction. 
It is evident from the foregoing characters that 
the lampreys are creatures of very simple form, 
lacking almost all the evidences of special develop- 
ment which characterize the higher fishes. Ex- 
ternally, their very modest median fins are the 
only visible signs that they are not marine worms. 
The Sea Lamprey 1 is the best and most avail- 
able example of the Class Mar-si-po-branch'ii. 
“The mouth is completely circular, and forms a 
great and powerful sucker, surrounded by fleshy 
lips that are supported on a framework of cartilage 
and studded with tentacles. This mouth is cov- 
ered over its entire interior surface with strong 
teeth arranged in concentric circles. A large 
double tooth, situated above the aperture of the 
mouth, indicates the situation of the upper jaw, 
and seven or eight great teeth represent the lower 
jaw. Even the tongue carries three large teeth, 
deeply serrated on their edge.” 2 
With a mouth specially formed and savagely 
equipped for suction, it is no surprise to find that 
this creature is a blood-sucking parasite, preying 
upon other forms of marine life. It is often found 
attached to shad, sturgeon, sharks, cod, halibut 
and mackerel. It fastens to its victim beneath 
the pectoral fins, tears at its flesh with its rasping 
circles of teeth, and sucks its blood “until the 
flesh becomes as white as paper. ” Beyond doubt, 
these creatures destroy a very considerable num- 
ber of valuable food fishes. Fishermen charge 
to the account of the Lamprey the raw spots and 
sores frequently found upon the bodies of stur- 
geons. 
Formerly the Lamprey was greatly esteemed 
by the people of Massachusetts as a food “fish.” 
In the Merrimac River it was captured in great 
numbers, and salted down for winter use. 
While this industry, and its object, have both 
greatly decreased, in some portions of Connecticut 
the Lamprey is yet taken, as often as it can be 
found, and thankfully consumed. The species 
specially mentioned varies in length from two to 
three feet, but the Brook Lamprey, and all the 
1 Pet-ro-my'zon ma-ri'nus. 
2 “ Fishery Industries of the United States,” 
Part I, p. 677. 
