206 BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



The spines of the dorsal surface of the disk, ordinarily very long: 

 and stout (as those which I show on plate 97 in figure la), become 

 sometimes very short, and then deserve the name of club spines (b). 

 In certain of these latter the teeth assume a very great development 

 toward the free extremity of the spine, while they tend to disappear- 

 along the rest of its length (e). In certain specimens, as for example 

 that from station 5519, the stem of these club spines shortens while 

 the terminal teeth become very greatly developed, and multifid club 

 spines thus pass into trifid and even bifid club spines, such as those 

 which I show here (fig. Id) ; certain of these last are remarkable for 

 the extraordinary development of the terminal spinules. 



I figure here the dorsal surface of two specimens coming, respect- 

 ively, from stations 5517 and 5523 (pi. 35, figs. 2, 3), as well as the 

 dorsal surface of a specimen collected by the Challenger. I include 

 these photographs not so much to show the very slight differences 

 which may be found between the two first individuals and the third 

 as to illustrate the resemblances and the differences which exist be- 

 tween O. aristulata and certain forms of O. fragilis. 



Doderlein ('10, p. 254) has given the name of O. aristulata to some 

 specimens of an Ophiothrix from the Bay of Liideritz, remarking 

 that the specimens show a very great resemblance to the variety 

 pentaphyllum of 0. fragilis. He recalls, moreover, that I have my- 

 self recorded that last species on the western coast of South Africa. 

 Doderlein concludes that the only character separating 0. aristulata, 

 from O. fragilis, var. pentaphyllum consists in the slightly different 

 armature of the dorsal surface of the disk. 



Since the publication of Doderlein's memoir I have had occasion 

 to study other specimens Ophiothrix from South Africa, from Swako- 

 munde and the Bay of Liideritz. I have mentioned these in a work 

 published in 1914 ('14c, p. 209), in which I wrote as follows: 



Ces exemplaires sont identiques a ceux que la Scotia a recueillis dans la Baie 

 de Saldanha (Cap) et que j'ai mentionnes en 1908 sous le nom d'O. fragilis var. 

 pentaphyllum ; ils me paraissent d'autre part etre parfaitement conformes a. 

 ceux que Doderlein a decrits en 1910 sous le nom d'O. aristulata et qui provien- 

 nent de la baie de Liideritz, autant que j'en puis juger d'apres les photo- 

 graphies publiees par ce savant. Ils s'ecartent au contraire des O. aristulata 

 que je possede dans ma collection et qui proviennent de l'Ocean Indien, et je- 

 crois devoir maintenir la determination k laquelle je me suis arrete en 1908. 



In referring to the photographs which Doderlein has published of 

 the Ophiothrix from the Bay of Liideritz I believe I am able to 

 state that that author had at hand not O. artistulata but the variety 

 pentaphyllum of O. fragilis. I can not find any difference between 

 the specimen photographed by Doderlein ('10, pi. 5, figs. 4, 5) and 

 the numerous individuals which I have in my collection of O. fragilis, 

 var. pentaphyllum from different localities on the coasts of France^ 



