464 PROCEEDINGS OF THE ACADEMY OF [DeC, 



more or less entirely whitish with slight leaden or grayish tints. Lower 

 surface of tail only narrowly pale. Dorsals and caudal pale brownish. 

 Disk pale brownish and teeth all dark or wood-brown. Iris pale slaty. 



Length 12|- inches. 



Type No. 375, A. N. S. P. Atlantic Ocean. Dr. T. B. Wilson. 



This is the only example I have seen. It is apparently related to 

 Petromijzon (Bathymyzon) bairdii Gill, Proc. U. S. Nat. Mus., 1883, p. 

 254, but differs, according to the account by Goode and Bean, Ocean. 

 Ichth., 1895, p. 4, in several characters. In B. bairdii the tips of the 

 two supraoral teeth are said to be barely perceptible, while in the 

 present species they are equally as well developed as either of the ad- 

 jacent bicuspids. In B. bairdii the eye is said to equal a fourth of the 

 interorbital space, while in the present species it is about a third. These 

 differences hardly seem due to age, as the type of B. bairdii and the 

 present species differ in length by only 1^ inches. Oceanomyzon will 

 then appear as an annectant form between the true lampreys, or 

 Petromyzon, and the bassalian Bathymyzon. 



(Named for Dr. Thomas B. Wilson, for many years a generous patron 

 of the Academy. Among his numerous gifts may be found much 

 valuable material in the collections of fishes.) 



Petromyzon marinus Linnaeus. 



Italy (Bonaparte Coll.); Boston, Mass. (J. H. Slack); Fannel's 

 Branch near Chestertown in Kent Co. (E. G. Vanatta), and Bacon 

 Hill in Cecil Co., Md. (H. W. Fowler). 



Petromyzbn marinus unicolor (De Kay). 



Cayuga Lake Inlet, N. Y. (S. E. Meek). 



Ichthyomyzon concolor (Kirtland). 



Two examples without data, and one from the Clinch River in Ten- 

 nessee (E. D. Cope). 



Ichthyomyzon castaneus Girard. 



Kiskiminitas River, Pa. (E. D. Cope). I wrongly identified this 

 example in Am. Nat., 1907, p. 6, as Lampetra irilderi. The species is 

 therefore now known for the first time in Pennsylvania. 

 Entosphenus tridentatus (Richardson). 



Willamette Valley, Ore. (0. B. Johnson). 

 Lampetra fluviatilis (Linnaeus). 



Italy (Bonaparte Coll.); Europe (Smiths. Inst.). 

 Lampetra cibaria (Girard). 



San Francisco Market, Cal. (W. N. Lockington). 



