66 BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



from 0. perfida. In his description he compared his new species 

 only with O. bairdi, from which it is obviously very different, and 

 he makes no mention of 0. perfida, to which it is extremely close. 

 The only difference which can be found is in the number of arm 

 spines. Doctor Clark states that there are five in a specimen with 

 a disk diameter of 10 mm., but as the number of these spines varies 

 and as in specimens with a disk diameter of 10 mm. the number 

 five is acquired very rapidly it is not possible to base a specific sep- 

 aration upon this character alone. I believe, therefore, that O. 

 lambda should be united with O. perfida. 



The Siboga met with 0. perfida between latitude 0-7 S. and 

 longitude 116-132 E., at depths varying from 411 to 959 meters 

 (225 to 525 fathoms). Doctor Clark's 0. lambda was dredged off 

 southern Japan in 32 N. latitude, 132 E. longitude, at a depth of 

 800 meters (437 fathoms). 



In his catalogue of the recent ophiurans H. L. Clark did not 

 recognize the genus Ophiolimna established by Verrill in 1899, the 

 type of which is O. bairdi (Lyman). In revising the genera Ophi- 

 oconis, Ophiochoeta^ and Ophiolimna Matsumoto redefined the lim- 

 its of the genus Ophiolimna and assigned to it, in addition to O. 

 bairdi, the two species which I described in 1904 and in 1909 under 

 the names of 0. perfida and O. operculataf as well as three species 

 previously placed in the old genus Ophioconis, O. antarctica Lyman, 

 0. diastata, and O. papillata H. L. Clark. He adds a seventh species, 

 0. lambda H. L. Clark, but, as I have just stated above, this last 

 does not differ from 0. perfida and falls into its synonymy. 



There must also be added to the genus Ophiolimna the Antarctic 

 species discovered by the Belgica which I described under the name 

 of Ophiaeantha polaris (Kcehler, '01, p. 32, pi. 3, figs. 19-21). 



I believe, like Matsumoto, that with the limitations ascribed to it 

 by the Japanese naturalist, the genus Ophiolimna is a perfectly well- 

 defined group ; it has certainly the same value as many of VerrilFs 

 other genera separated out from the old genus Ophiacantha, such as 

 Ophiopristis, Ophiotreta, Ophialcoea, Ophientrema, etc. There 

 would be more reason to suppress these latter than the former. 



In his memoir of 1917 Matsumoto maintains the genus Ophiolimna 

 with the same characters and with the same species as in 1915 ('17, 

 p. 101). 



*In mentioning O. operculata H. L. Clark remarked that there is a lack of agreement 



itive to the date and the depth between the figures which I gave in my preliminary 



report in 1907 and those in my final memoir published in 1909. He believes that the 



atter are correct. The figures which I published in 1907 were, as he believes, later 



ised, and it is the information given in my memoir which is correct; the species 



ally comes from the enormous depth of 5,869 meters (3,209 fathoms). I may remark 



that II. L. Clark himself has made a slip of the pen in citing O. opcrculata lie has 



written O. opcrcitlaris ('15, pp. 207, 368), which is incorrect. 



