"by invest igator s, oecause they have not sought for 

 them under the skin. 



Since the Pennella species on the one side 

 present only a few external character s for tne sep- 

 aration of the species, and since on tne other nand 

 tne individual variations in the proportions of tne 

 various oody regions are much larger tnan we sup- 

 pe sed,we have taken pains to compare mutually many 

 individuals of the same species, and also as far as 

 possible various specimens from the same host, in 

 order that there"by we might escape the uncertainty 

 in the comprehension of the fundamental differences 

 oetween the individual forms,which is the necessary 

 result of the aoove mentioned methods. 



Whenever a fine Museum specimen lilce Chironectes 

 was infested with various Pennellas we have never- 

 theless chosen in the interests of science to rt- 

 move these parasites from it^partly for mutual com- 

 parison,partly for comparison with whatever species 

 might stand nearest to them* 



With reference to our specimens we may af firm 

 that the figure given "by Nordmann in Mikrog.Beit. 

 II,taD.X,f ig.6,f ive times enlarged,correctly rep- 

 resents our species and Linnaeus 1 P.sagitta,and 



that our specimens were taken from the same f isn. 



