8 BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



Regarding these suggestions I may say that in general they are 

 of purely secondary importance and do not affect the broad lines of 

 the classification established by Matsumoto. It is also fair to men- 

 tion that H. L. Clark stated that if his classification differed from 

 that of Matsumoto it was not at all because he had found the latter 

 at fault. I quote his own words : 



It must not be inferred that in those instances where I have not followed 

 Matsumoto I indicate a belief that he is wrong. It merely shows that I have 

 not yet satisfied myself as to the relationships of certain genera and species. 

 In these cases, notably in regard to the genus Ophioconis and its allies, the 

 evidence is perplexing and more light is necessary ('15, pp. 165, 166). 



Matsumoto has elaborated his conclusions in a magnificent work 

 published in 1917, entitled "A Monograph of Japanese Ophiuroidea 

 Arranged According to a New Classification," 1 which reached me 

 just as I was about to send my report to Washington. I have thus 

 not been able to make use of it in the preparation of this memoir, 

 begun three years previously, though I have been able to insert in 

 the text the bibliographical references, as well as some notes on dif- 

 ferent points on which I am not entirely in accord with the learned 

 Japanese naturalist. 



Matsumoto divided the ophiurans into two primary classes, namely r 

 CEgophiuroida, including only fossil forms with an external ambu- 



lacral groove and without ventral arm plates, and 

 Mtophiuroiua, without an external ambulacral groove and with 

 ventral arm plates, including certain paleozoic species and all 

 known living forms. 

 The latter is divided into four orders : 



Phrynophiurida, with three families : 

 Ophiomyxidae. 

 Trichasteridae. 

 Gorgonocephalidae. 

 Laemophiurida, with two families : 

 Hemieuryalidae. 

 Ophiacanthidae. 

 Gnathophiurida, with three families : 

 Amphiuridae. 

 Amphilepididae. 

 Ophiotrichidae. 

 Chilophiurida, with five families: 

 Ophiochitonidae. 

 Ophiocomidae. 

 Ophiodermatidae. 

 Ophiolepididae. 

 Ophioleucidae. 



1 Journ. Coll. Sci., Imp. Univ. Tokyo, vol. 38. art. 2. 



