2 ART. 2. — H. MATSUMOTO ; 



My own study of this group was undertaken at the sugges- 

 tion of Prof. Goto, to whom my thanks are due for supervision 

 and the revision of the manuscript. Dr. Takahashi of the First 

 High School and Mr. Ikeda of the Seventh High School have 

 kindly permitted me to study the specimens in their charge. I 

 owe specimens to many other friends, to all of whom my hearty 

 thanks are due. Especially, I have received a great help from 

 Dr. HuEBERT L. Claek of the Museum of Comparative Zoology at 

 Harvard College, in the form of many precisely determined speci- 

 mens in his charge and of some very helpful advices, and my 

 best thanks are due to him ; and it was due to his kind sugges- 

 tion that a preliminary paper of the present study was published 

 in America. Finally, I ever recall in mind my friend, Hideki 

 Chiba, who met with an untimely death a few days after assisting 

 me in dredging for my materials in the Sagami Sea, and to his 

 memory I dedicate the present paper. 



My original purpose in undertaking the present study was 

 merely to identify and name species. But I soon found that, the 

 classifications of Ophiuroidea hitherto proposed were very unsatis- 

 factory. Indeed, their imperfections became a haunt to me ; so I 

 determined to adopt a new classification of my own. 



For this purpose, I have dissected representatives of as many 

 genera as are accessible to me; and the following are some of the 

 more important results obtained. 



A. Morphological. 



1. Those forms that have arms, which are capable of being 

 coiled vertically, have very compact oral skeleton : the adorai 

 shields are entirely proximal to the oral shield, being firmly united 

 to it ; the oral frames are very stout, those of the same radius 



