Nachdncck verboten. 

 Uebersetzungsrecht vorbehalten. 



On certain Features of the Lateral Canals and Cranial 

 Bones of Polyodon folium. 



By 

 Edwards Phelps AUis jr., Menton. 



With plate 28 and 2 figures in text. 



I have lately received a considerable amount of material collected 

 in the United States before the temporary closing of my Lake Labo- 

 ratory at Milwaukee, Wisconsin. Among other things there were 

 several very badly preserved heads of Polyodon folium, one entire 

 specimen, about one foot long, of the same fish, and an incomplete 

 and somewhat broken set of the dermal bones of the head. 



As I have never been able to fully accept, or even to fully 

 comprehend, certain of Collinge's statements (7) regarding the 

 lateral sensory system of this fish, and as the investigations with which 

 I am at present occupied lead me to make frequent references to his 

 work, I have immediately attempted to control that work in so far 

 as my material would allow. The condition of my material has, un- 

 fortunately, limited this control almost exclusively to the general 

 distribution of the lateral canals, and their relations to the several 

 cranial bones. This limited investigation has, however, not only con- 

 firmed, as 1 expected, certain inaccuracies in Collinge's description 

 of the canals and surface sensory organs, but also, and most un- 

 expectedly, led to the discovery of certain errors and omissions in his 

 and Bridge's (6) descriptions of the cranial bones of the fish. 



Before beginning the descriptions of the canals and their related 

 bones, reference must be made to certain descriptive terms used and 

 misused by Collinge. 



Under the heading "Nomenclature" this author says (p. 504): 



"3. A system of fine dermal canals running from the main canal 

 or a branch of the same, and opening by a series of fine branches to 

 the surface by isolated pores, will be termed cluster pores (peripheral 

 organs of Allis)." 



