Occasional Papers of the Musenin of Zoology ii 



Anterior lingual lamina with a Anterior lingual lamina with an- 



single transverse element, which terior and posterior transverse 



is provided with minute round- elements, each provided v.ith 



ed denticles. prominent sharp denticles. 



Anal fin well developed, particu- .Vnal nn usually lacking; when 



larly in females, present it is low and not prom- 

 inent.^ 



Xo specific larval characters have been worked out. 



Bibliography. 



Dkax, Basiiford and Su mxkr. Kraxcis B. Notes on the 

 vSpawning Habits of the Brook I,amprey ( rdroiny.^oii icHd- 

 rn\ Trans. X Y. Acad, v'^ci., XVT. 1S97. 



Fowler, II. W. Xotes on Lancelets and Lampreys. Proc. 

 Acad. Xat. Sci. Philad., LIX, 1907. 



Gage, S. H. and AIeek, S. E. The Lampreys of Cayuga Lake. 

 Proc. Amer. Ass. Adv. Sci., XXXA', 1886. 



Gage, S. H. The Lake and Brook Lampreys of X'ew York, 

 especially those of Cayuga and Seneca Lakes. Wilder Quar- 

 ter-Century Book, 1893. 



Gage, S. II. Transformation of the Brook Lamprey (Lai-i- 

 pctra "icildcri), and Parasitism among Lampreys. Proc. 

 Amer. Ass. Adv. Sci., XLMI, 1898. 



Gill, Theodore. X'ote on the Petromyzontids. Proc. U. S. 

 Xat. Mus.. 1882. 



^ Girard's generic diagnosis of Ichthyomyzon definitely states that there is no 

 anal nn, and his type specimens do not exhibit this structure. But the junior 

 author has examined, in the U. S. Xational Museimi, individuals which have the 

 anal fin. Its presence or absence cannot then be considered a generic character. 

 Very likely it is of seasonal appearance in the typical Ichthyomyzons. 



