Z ART. 4. J. IKEDA : 



this identification could in several cases be made only with a 

 greater or less degree of doubt as to its correctness. This is due, 

 I think, mainly to the excessive conciseness of terms in which 

 most of the old species (especially in the Echiuroidea) were 

 described. 



I have not deemed it necessary, for the present at least, to 

 create a new genus for the reception of any of the new species, 

 although the thought frequently suggested itself to my mind that 

 some of the forms, e.g. Thalassema tœnioides n. sp., might well 

 be made the type of a distinct genus. 



At the end of the paper will be given a key to all the 

 species treated of, which may help students of the same field in 

 the task of identification. 



For the purpose of obtaining my material I have made 

 frequent visits to the Misaki Marine Laboratory. Further I may 

 mention that on a collecting trip to the Island of Amani-Oshima 

 (Province of Satsuma) and the Islands of Riukiu in 1901, and 

 on others to the Province of Aomori in 1900 and to Gogoshima 

 (Province of lyo) in 1903, special attention was paid to the 

 Gephyrean fauna. 



To a number of friends, whose names will be mentioned in 

 the proper places, I am indebted for gifts of several valuable 

 specimens, some of which I should otherwise have been unable 

 to obtain. 



