44 
BULLETIN OF THE BUREAU OF FISHERIES 
The lampreys attach themselves to larger fish by means of the suctorial mouth, sucking their 
blood and making ulcerous sores, often producing death. Surface (1898, p. 212), in an account 
of the variety P. marinus unicolor, records that this lamprey destroyed large numbers of catfish, 
suckers, carp, etc., in Cayuga Lake, New York. Shad are sometimes taken with lampreys 6 to 14 
inches in length hanging on their sides. Kendall (field notes, 1894) reports a 10-inch lamprey 
clinging to a menhaden only 6 inches in length. Bigelow and Welsh (1925, p. 20) report lampreys 
preying upon cod, haddock, and mackerel in Massachusetts Bay. At one time lampreys were said 
to be common in the Chesapeake during the early spring and to have destroyed many shad caught 
with gill nets. Within recent years, however, it has not been sufficiently abundant in Chesapeake 
Bay to be considered destructive of other fishes. 
This lamprey is anadromus and ascends fresh-water streams in the spring to spawn, coming with 
the shad and branch herring. The number of eggs produced is large, as many as 236,000 having 
been found in one individual. The young differ considerably in appearance from the adults. They 
are blind and toothless and their mouths and fins are different in shape. They live in this state in 
fresh water for about three or four years and then undergo a transformation, after which they 
descend to the sea. When mature they return to fresh water to spawn but once and then die. 
The young have been found to subsist on minute organisms. The stomachs of adults, while 
usually containing only blood, have been reported by Goode (1884, p. 677) to occasionally contain 
large numbers of fish eggs. 
Fig. 25 . — Petromyzon marinus 
This species attains a length of 3 feet, although seldom exceeding 2^ feet. In the past, when 
it was more plentiful, it was used for food in parts of New England, while in Europe it has been 
considered a delicacy for many years. In Chesapeake Bay the lamprey is of no commercial value. 
Habitat. North Atlantic coasts of Europe and North America; on the American coast from 
Labrador south to Florida. 
Chesapeake localities.— (a) Previous records: Potomac River and many points in the upper 
parts of the bay. ( b ) Specimens were taken during the present investigation (during April and 
May' at Havre de Grace, Md., and Lynnhaven Roads, Va.; also observed in the lower Patuxent 
River, Md., and Kendall reports (field notes, 1894) several from Hampton, Va. 
Class ELASMOBRANCHI! 
Subclass SELACHII. The sharks, skates, and rays 
Order EUSELACHXI 
Family HI— 0RECT01QBID4£. The nurse sharks 
Body short and subcylindrical to moderately short and depressed; nostrils with a nasoral 
groove and with a cirrus or barbel; mouth transverse, with labial folds around angles; teeth com- 
pressed with or without lateral cusps on each side of the median one; eyes very small, without 
nictitating membrane; spiracle minute and behind eye to large and more or less below it; gill slits 
small to medium, the posterior two or three above base of pectoral; caudal fin narrow, usually 
without exerted lower lobe; other fins short and broad, no fin spines; no caudal pits. 
