456 



NOTES ON PROSOBRANCHIATA, 



A comparison of the species in detail would show a single 

 related species in all four localities, and, therefore, give an erroneous 

 impression that the lieds were of similar age. 



The Evidence of Literature. 



A detailed examination of literature has resulted in the dis- 

 covery of greater support for the arguments I have advanced 

 than I expected when writing the last part of this paper. I have 

 found that the majority of the species spoken of as being referable 

 to or connecting two of the divisions proposed by Tryon and 

 others have been, by different writers, placed in both sections. 



Tryon (37, 9) says : — " The species of Triton being numerous 

 several attempts have been made to separate them into generic 

 or subgeneric groups, the most successful being the arrangement 

 of Messrs. H. and A. Adams (1)." Previous arrangements never 

 having attained any degree of acceptance, I will date my com- 

 parisons from this one. Subsequent classifications are those of 

 Kobelt (20), Gray (13), Fischer (12), Chenu (5), Tryon (36), Melvill 

 and Standen (24), and Dall and Simpson (s). Kobelt's arrange- 

 ment being the same as Tryon's, and Chenu's the same as that of 

 H. and A. Adams, they are not included in the following table : — 



Generic names in small capitals, subgeneric in italics, group names in 

 black type. 



