The Lake and Brook Lampreys of Nezv York 423 



Problems having a philosophical bearing have always been 

 the most fascinating to the natural philosopher as well as to 

 the metaphj'sician. In the study of living organisms this has 

 been especially true since the doctrine of evolution has so 

 profoundly influenced thinking men. Naturally therefore, 

 Professor Wilder, who came to his professorship in Cornell 

 University — which itself was making a leap in educational 

 evolution — during the time when evolution and various col- 

 lateral hypotheses were in the fiercest conflict with all previous 

 doctrines, theological and otherwise — naturally Professor 

 Wilder turned with especial interest to the study of the Cayuga 

 I^ake fauna which promised information concerning the effect 

 of local environment, and change from preceding conditions. 

 Naturally also he turned with especial interest to the lamprey, 

 the lowest representative of the vertebrates found in the lake 

 fauna. 



This interest was transmitted to his pupils, and since 1875 

 the writer of this article has lost no opportunity of studying the 

 lampreys at all stages of life, and this study has been devoted 

 to the living animals rather than to the dead organisms, al- 

 though the understanding of their activities and physiological 

 functions has been constantl}^ clarified by experiment and an- 

 atomical study. 



Characterized zoologically the lampreys (Petromyzontidse) 

 are fish like vertebrates, with an eel- or snake-like form and 

 a metamorphosis, comparable to that of frogs and toads. The 

 skeleton is wholly cartilaginous and the notochord persistent. 

 Neither pectoral nor pelvic limbs nor their arches are present 

 although the dorsal and caudal fins are well developed. The 

 branchiae are extended, and open by seven independent 

 openings on each side, and in the adult the gills are pouched 

 (whence the name Marsipobranchii sometimes used). The 

 nasal sac is single and blind and opens to the exterior by a 

 raised papilla on the dorsimeson just cephalad of the median, 

 or pineal, eye and of the paired eyes. Apparently no jaws 

 are present and the mouth in the adult is suctorial and armed 

 with horny teeth; but the rudiments of jaws have been shown 

 by Huxley and others to exist. The tongue is a piston-like 

 rasp in the adult, absent or rudimentary in the larva. 



