356 CYCLOSTOMATA. 



Family I— PETROMYZONTIDJ^:. 



Body eel-shaped : scaleless. The single nasal aperture on the top of the head, 

 and terminates in a blind sac. A metamorphosis occurs in members of this 

 family attaining adult age when the mouth is suctorial, and armed with teeth 

 besides the maxillary, mandibular and lingual ones. Eyes present in adults. Seven 

 branchial openings on each side of the neck, the gill being in a sac, the inner 

 duct ending in a common tube. Eyes small. 



The larval f ornas are destitute of teeth, and the eyes are almost invisible : the 

 young, even of anadromous forms, said to remain several years in the fresh water. 



Genus I — Peteomtzon,* Artedi. 



Lampetra, Gray. For larval forms Ammoccetes, Dumei-il: Scolecosoma, Girard. 



Definition as in the family. iHfa.villary teeth two, placed close together. Mandi- 

 bular ones in a semi-circnlar ridge, serrated ones on the tongue. Two dorsal fins, 

 the posterior continuous tvith the dorsal. 



1. Petromyzon marinus, Plate CLXXVIII. 



Lampetra s. 2Iustela, Belon. p. 76; Rondel, p. 398; Willughby, p. 105, t. 

 G2, f. 2 ; Ray, Synop. Pise. p. 35. Lampetra maculosa and major, Salvian. f . 63a, 

 636; Aldrov. p. 539; Jonston, p. 117, t. xxiv, f. 5 ; Rutty, Nat. Hist. Co. Dublin, 

 1772, i, p. 35l. Petromyzon, sp. no. 2, Artedi, Synon. p. 90 and Genera, p. 64. 

 Sea-lamprey, Pennant, Brit. Zool. (Ed. 1776) iii, p. 76, pi. viii (Ed. 1812), iii, 

 p. 102, pi. X. 



Petromyzon marinus, Linn, i, p. 304; Bloch, loh. pi. Ixxvii, and Hist. Nat. 

 p. 653, t. Ixxvii ; Bonnaterre, Ency. Ich. p. 1, pi. i, f . 1 ; Gmel. Linn. p. 1513 ; Lacep. 

 i, p. 3, pi. i, f . 1 ; Bl. Schn. p. 530 ; Donovan, Brit. Pish, iii, pi. Ixxxi ; Turton, p. 109 ; 

 Mitchell, Lit. and Phil. Trans. New York, i, p. 481 ; Risso, Ich. Nice, p. 1, and Eur. 

 Merid. iii, p. 114 ; Fleming, Brit. An. p. 163; Jenyns, Manual, p. 520 ; Parnell, Wem. 

 Mem. vii, p. 442 ; Yari-ell, Brit. Fishes (ed. 1) ii, p. 448, c. fig. (ed. 2) ii, p. 598 

 (ed. 3) i, p. 32; Templeton, Mag. Nat. Hist. 1837 (2) i, p. 413; Johnston, 

 Berwick. N. H. P. Club, 1838, i, p. 176; Gray, Catal. Chondr. p. 138 and 

 Proc. Zool. Soc. 1851, p. 235, pi. iv, f . 1; Swainson, Fishes, ii, p. 338; Nilss. 

 Skan. Faun, iv, p. 743 ; Selys-Long. Fauna Belg. p. 226 ; Kroyer, Danm. 

 Fist, iii, p. 1025 c. iig. ; White, Catal. p. 143 ; Heckel and Kner, S. W. F. 

 p. 374, f. 200, 201 ; Siebold, S. W. P. p. 368 ; Thompson, Nat. Hist. Ireland, 

 iv, p. 264 ; Schlegel, Dieren Neder. p. 204, pi. xxi, f. 2, 3 ; Blanchard, 

 Poiss. Franc, p. 612, fig. 137; Canestrini, Faun, d'ltal. Peso. p. 31; Giinthex-, 

 Catal. viii, p. 501 ; Collett, Norges Fiske, p. 218 ; Houghton, Brit. F. W. Fish, 

 p. 193, c. fig. ; Winther, Prod. Ich. Dan. Mar. p. 61 ; Feddersen, p. 94 ; GiglioH, 

 Cat. Pesc. Ital. p. 55 ; Moreau, Poiss. de la France, iii, p. 602, fig. 217. 



Petromyzon lampetra, Pall. Zoo. Ross. -As. iii, p. 66. 



Petromyzon Americana, Lesueur, Trans. Am.er. Phil. Soc. i, p. 382 ; De Kay, 

 New York Fauna, Fish, p. 379, pi. Ixvi, f. 216 ; Storer, Mem. Amer. Acad, ix, 

 1867, p. 251, pi. xxxviii, f, 4. 



Petromyzon maculosus, Gronov. ed Gray, p. 2. 



Lampetra marina, Malm, Fauna, p. 630. 



Sea-iamprey, Couch, Fishes Brit. Isles, iv, p. 385, pi. ccxlvii, f. 1. 



Body eel-shaped, round anteriorly, becoming compressed posteriorly. Eyes not 

 much larger than one of the branchial orifices and covered by the skin. Nasal 

 aperture on the anterior portion of the interorbital space. Mouth surrounded 



* See notes on the Lamprey, by G. Brown Goode, Bull. United States Fish Commiesion, 1883, 

 p. 349. 



