up and the anterior end is nearest the- top of the page, 

 then the readers left is also left in the figure. 



For convenience in description, the various stages 

 taken to illustrate the life history of the species 

 have been designated by letters of the alphabet; this 

 method seeming preferable to one in which age is used 

 as a distinguishing character, since the progress of 

 development at any ace depends so intimately on the 

 varying conditions of environment. 



I take this opportunity to acknowledge m$ indebt- 

 edness to Dr.C.P.Sigerfoos at whose suggestion I began 

 the study of Ophiuran development. 



I was aided very materially while at the Fish Com- 

 mission laboratory by Prof .H.C.Bumpus who placed at my 

 disposal every facility for work at his command and to 

 him also I am greatly indebted for many suggestions in 

 methods of rearing larvae at the sea-shor* . 



To Prof. Brooks, under whose direction my, work 



o/yu 



has been done, is due my warmest thanks for the inter- 

 est with which ho has followed me in my studies and 

 ^rr the many valuable suggestions he has offered from 

 time to time during the year. 



