2 FISHES OF PENNSYLVANIA. 

Genus PETROMYZON (Artep1) Linyzuvs. 
2. Petromyzon marinus Linyzvs. 
The Sea Lamprey. (Figure 17.) 
Body cylindrical, eel-like, stout, somewhat compressed behind. The mouth is 
terminal, subcircular inshape and suctorial. It is strongly armed with large conical 
teeth or cusps mounted on papille, those of the inner series being bicuspid. Guard- 
ing the throat are crescent-shaped plates, bearing pectinate lingual teeth; a pair of 
these plates on either side and another pair below them. The mandibulary plate has 
seven cusps. There are seven branchial apertures on each side of the head, the first 
not far behind the eye; the distance of the last opening from the tip of the snout is 
contained about five times in the total length. Eye rather small, covered with mem- 
brane. The first dorsal originates in about the middle of the length; it is little 
developed and well separated from the second dorsal, which is confluent with the 
anal, The anal is very low and only about one-half as long as the second dorsal. 
The vent is far back, opposite the origin of the second dorsal. The specimen exam- 
ined is twenty-eight inches long, and is No. 10654 in the United States National 
Museum collection. 
‘The sea lamprey or lamprey eel inhabits the north Atlantic, ascending 
streams to spawn and sometimes becoming landlocked. In some interior 
waters of New York the landlocked form has received the name wnicolor 
of DeKay. The species ranges southward on our coast to Virginia. In 
the Delaware, Susquehanna and their tributaries this is a common fish. 
Its larval form, which is blind and toothless, is extremely abundant in 
muddy sand flats near the mouths of small streams, and is a very im- 
portant bait for hook and line fishing. The sea lamprey grows to a 
length of three feet. It is dark brown in color, mottled with blackish 
and whitish. In the breeding season in spring the males have a high 
fleshy ridge in front of the dorsal. The spawning is believed to take 
place in May or June. The eels cling to the rocks by means of their 
suctorial mouths, and the eggs are deposited in shallow water on a rough 
bottom where the current is swift. Some observers state that they make 
nests by heaping up stones in a circle and deposit the eggs under the 
stones. The ovaries are large, but the eggs are very small. The food of 
the lamprey is chiefly animal matter, and the fish is somewhat of a para- 
site, burrowing into the side of shad, sturgeon and some other species. 
The teeth are adapted for this method of feeding. The tooth-bearing 
bone of the upper side of the mouth contains two teeth which are placed 
close together. On the bone corresponding with the lower jaw there 
are seven or nine stout cusps. There are numerous teeth around the 
disk; the first row on the side of the mouth contains bicuspid teeth; 
the others are simple.. The tooth on the front of the tongue has a deep 
median groove. The species is adapted for fastening itself to other fishes 
and extracting from them their blood. The lamprey is considered a 
good food fish in some localities, but in other places it is rarely eaten. 
In Connecticut and Massachusetts the species is highly esteemed. It is 
preserved by salting for several weeks before using. The fish are some- 
times caught with the hands and by means of a pole armed with a hook. 
