CYCLOSTOMES. 
1183 
THE SEA LAMPREY (sw. hafsnejonogat). 
PETROMYZON MARINUS. 
Plate LIII, fig. 1 . 
Anterior ling no dental plate medially recurved and hollowed from in front. Teeth on the anterior dental plate of 
the mouth contiguous at the base. Length of the suctorial disk ivhen closed {in adult fishes ) more than half that 
of the head to the first gill-opening . 
Syn. Mus tela, Auson., Mos., vers. 107. Lamproye de mer, Belon, 
Nat., Div. Poiss., p. 66. Lampetra a , Rondel., De Pise., 
p. 398. Lampreta 1. Lampreda b , Gesn., De Aquatil., p. 
592; Paralip., p. 22. Petromyzon c maculosus, ordinibus 
dentium circiter viginti, Art., Ichthyol., Gen. Pise., p. 64; 
Syn. Pise., p. 90. StrOm, Sondm. Beskr., pt. I, p. 297 
( Neyenogen ). Sea-Lamprey, Penn., Brit. Zool. (ed. 1776), 
vol. Ill, p. 67, tab. VIII, No. 27. 
Petromyzon marinus, Lin., Syst. Nat., ed. X, tom. I, p. 230; 
Fna Suec., ed. II, p. 106; Gdnn., Trondhj. Selsk. Skr., 
vol. IV (1768), p. 22, not.; P>l., Fische Deutscld., pt. Ill, 
p. 38, tab. LXXVII; Retz., Fna Suec. Lin., p. 302; 
Born, Zeitsclir. Organ. Phys. (Heusinger), Bd. I (1827), p. 
170; Nilss., Prodr. Ichthyol. Scand ., p. 121; Yakr., Brit. 
Fish., ed. 1, vol. II, p. 448; Sel. Longoh., Fne Beige, 
p. 226; Kr., Danin. Fisk., vol. Ill, p. 1025; Nilss., 
Skand. Fna, Fisk., p. 743; Hckl, Kn., Siisswasserf. Ostr. 
Mon., p. 374; Sieb., Siisswasserf. Mitteleur ., p. 368; Malm 
( Lampetra ), Gbgs Vet., Vitt. Samh. Hand!., Ny t.idsf ., H. 
VIII (1863), p. 87; Mgrn {Lampreta), Finl. Fiskfna (disp. 
Helsingf. 1863), p. 75; Couch ( Petromyzon ), Fish. Brit. Isl., 
vol. IV, p. 385, tab. CCXLVII, fig. 1 ; Blanchard, Poiss. d. 
eaux douees d. 1. Fr., p. 512; Canestr., Arch. Zool., Anat., 
Fisiol. (Modena), vol. IV, p. 184; Gthr, Cat. Brit. Mus., 
Fish., vol. VIII. n. 501; Coll., Forh. Vid. Selsk. Chrnia 
1874, Tilhegsh., p. 218; 1879, No. 1, p. 106; N. Mag. 
Naturv. Chrnia, Bd. 29 (1884), p. 122; Malm, Gbgs, Boh. 
Fna, p. 630; Winth., Naturh. Tidskr. Kbhvn, ser. 3, vol. 
XII, p. 61; Feeders., ibid., p. 94; Mor., Hist. Nat. Poiss. 
Fr., tom. Ill, p. 602; Bncke, Fisch., Fischer ., Fischz. 0., W. 
Preuss., p. 194; Mela, Vert. Fenn., p. 369, tab. X; Day, 
Fish. Gt. Brit., Irel., vol. II, p. 356, tab. CLXXVIII; Fremy, 
Coinpt. Rend. Acad. Par. 1883, No. 11 (Mars 2), p. 721; 
MSb., Hcke, Fisch. Osts., p. 159; Jord., Ford., Ann. New 
York Acad. Sc., vol. Ill, p. 283; Lillj., Sv., Norg. Fna , 
Fisk., vol. Ill, p. 719. 
Petromyzon Lampetra, Pall., Zoogr. Ross. Asiat., vol. Ill, 
p. 66. 
Petromyzon Americanus, Lesueur, Trans. Amer. Phil. Soc. 1818, 
p. 373 (+ Petr, nigricans , p. 385); Dek., New York 
Fna, pt. IV, Fish., pp. 379 et 381, tab. 66, fig. 216; tab. 
79, fig. 247; Stor., Mem. Amer. Acad. Arts, Sc., N. ser., 
vol. IX, pp. 251 et 253, tab. 38, fig. 4; tab. 39, fig. 6. 
Ammocoetes bicolor, Lesueur, 1. c., p. 386; Dek., 1. c., p. 
383, tab. 79, fig. 248; — forrnam larvalem hujus speciei cen- 
suerunt Jordan et Fordice, 1. c. 
Petromyzon appendix , Dek., I. c., p. 381, tab. 64, fig. 211. 
Ammocoetes unicolor, Dek., 1. c., p. 383, tab. 79, fig. 250; 
— form, larval, sec. Jord., Ford. 
Petromyzon maculosus, Gronov., Cat. Fish., ed. Gray, p. 2. 
The Sea Lamprey attains a length of about 1 m. 
and a weight of about 1 x / 2 kilo. Still larger speci- 
mens, weighing at least 27 4 kilo., are indeed adduced d , 
but are certainly rare. According to Linnjeus* Wahl- 
bom caught at Calmar a Lamprey of an arm’s thickness. 
In spite of its dimensions this species undergoes its 
metamorphosis from the larval stage at a length of 
only about 3 / 4 — lV 2 din.' 
The body is Eel-like, anteriorly terete or showing 
some lateral compression, which increases more and 
more behind. The greatest depth, about half-way be- 
tween the last gill-opening and the beginning of the 
first dorsal tin, is about 7 or 8 % of the length of the 
body. Behind the body gradually tapers; but even at 
the space between the two dorsal tins the depth is about 
5 or 6 % of the length. In front the depth is more 
constant forward to the head, the form of which is 
determined by the singular snout. When the fish is 
not attached to any object, the snout is not unlike an 
inverted spoon; but the under surface, the sucking-disk, 
can alter its position, when the fish attaches itself, till 
the snout terminates in a more or less vertical, broadly 
“ “A lambendis petris”. 
6 Ex lampen , German. — dependere. 
c “A TtstQOQ lapis et uvQio s. Livid oj sugo, quia sugendo lapidibus ad I ue ret in fluviis”, Philos. Ichth., p. 73. 
d Pennant, Brit. Zool., vol. Ill (ed. 1776), p. 68; Day, 1. c., p. 359. 
e Fna Suec., 1. c. 
I Dekay states the length of Petromyzon appendix at 101 — 152 mm. Storer adduces a length of 76 — 178 mm. for Petrom. nigri- 
cans. In Scandinavia Schagerstr6m (according to Lilljeborg), Malm, and Collett have found fully developed Sea Lampreys about 14 * 1 * 2 cm. 
long. The larvae {Ammocoetes unicolor) attain, according to Dekay, a length of at least about 1 dm. 
Scandinavian Fishes. 
149 
