406 
MUD LAMPREY. 
from the fact that the tide is known to flow at times over a 
place where they lie hid; and they live longer on the hook at 
sea than the Silver Lamprey is known to do. 
This fish is widely distributed in Europe, and even in the 
north; although it has been said that it is not known in Britain 
north of the Tweed, and it is not noticed by Nillson among 
the fishes of Scandinavia. But I am informed by Mr. Peach 
that it is common at Wick. It is classed with the fishes of 
Hungary by Dr. Reisinger. Its time of shedding spawn is in 
the spring, and an instance is known of its having done this 
in captivity. The grains were white, and in size a little less 
than those of a lobster; but it is probable that they were not 
fertile. 
The usual length of this species is about six inches, with 
the circumference of a large goose-quill; hut the enlargement 
is greater along the course of the gill openings. The expansion 
of the mouth is not cireular; but the upper lip is wide, arched 
into a half circle, and capable of complicated motion; in life 
well charged with blood-vessels; the lower lip lying across, and 
it is believed capable of being thrust forward considerably, or 
rather lifted up, so as with the aid of the sides of the lips to 
cover the orifice of the gullet. The teeth are not firm, but 
they exist; a wide border of small ones above, and behind a 
pair of larger, a pair much larger below. A curious action is 
seen in life at the place where the passage from the forehead 
Dommunicates with the gills; and by which it is probable the 
water for breathing is supplied to the branchiae, as a substitute 
for the ordinary gill-covers of other fishes. The orifice on the 
head is fiir forward. The orifices of the gills are marked with 
circular lines, each having its own blood-vessel, and which 
also are discerned at regular intervals along the body; the body 
itself round until behind the vent, where it is compressed. 1'he 
eyes are small, and not to be discerned without much attention, 
situated in a depression, which resembles a channel forward 
and backward; with a projection above them which serves to 
guard and also to conceal them. The vent is far behind, 
opposite an early portion of the second dorsal fin. The first 
dorsal begins at about the middle of the length, and is narrow; 
sometimes so much so as scarcely to be discerned; the second 
a little removed from the first, wider near its beginning, and 
