12 BULLETIN li, UNITED STATES NATIONAL MUSEUM. 



Indian seas and it is thus jjrobable that it has also been dredged by tlie Blale and, 

 hkewise, inchi<ied under Dorocidaris papilhta. Whether Chirk has included this 

 species under " Tretocidaris" ojfinis, I can not say; but in any case he must certainly 

 have seen some of the si)ccimens mentioned above, since he has examined the col- 

 lection of cidarids in the U. S. National Museum. 



I have been in some doubt whether I should mention this form as a new species 

 or only as a new variety of affinis. The distinguishing characters are certainly 

 not very important, and the material at hand is small (I have not examined 

 very closely all the specimens mentioned above as seen in the U. S. National 

 Museum). Juilging from the material at my disjjosal it would appear to be 

 quite evident that we have here a distinct species; but Clark's statement that affinis 

 is so very variable in color makes me hesitate in creating a new specific name for 

 this form. However, I have taken this course in view of the fact that the differ- 

 ences in the ambulacra and in the tridentate pedicellarise seem to afford very good 

 specific characters; in addition to which the length of the spines, the brown bands 

 on the test, and the total lack of red on the secondary spines contribute to make 

 this form appear very characteristic. Should it ever prove untenable as a separate 

 s])ecies no great harm will have been done, for, in any case, it will certainly be 

 necessary to keep it as a distinct variety. 



The reference of affinis to the genus Tretocidaris in Clark's important work 

 The Cidaridffi, I have criticised in my report on the Ecliinoidea of the German 

 Southpolar Expedition, pages 51-52, to which work I may refer. I venture to 

 hope that I have there made it sufficiently evident that this disposition of it was 

 erroneous. The genus Stylocidaris was established there for the group of species 

 related to affinis, which was made the genotype. 



In the Challenger Echinoidea Mr. Agassiz ascribes to Cidaris cidads {Doroci- 

 daris papillata) an almost cosmopolitan distribution; the North Atlantic, from 

 Norway to the Canaries, the West Indian seas, La Plata, the Philijipines. The same 

 distribution is still given for this species in his magnificent work The Panamic Deep 

 Sea Echini (p. 228). In my work on the Ingolf Echinoidea I was able to restrict 

 this enormous range considerably, finding the specimens from off La Plata and 

 the Pliilippines to belong to widely different forms, none of them really being 

 of the same genus as the "Dorocidaris papillata," to which they were referred.** 

 As for those from the West Indies, I thought they might really prove to be 

 identical with the form from the Norwegian Sea and the Northern Atlantic (except- 

 ing, of course, Stylocidaris affinis, which was also previously regarded only as a syno- 

 nym of Cidaris cidaris). Having, however, no specimens of the West Indian form 

 except two of C. abyssicola, I could form no definite opinion on the ciuestion. It is 

 true that I had examined some specimens in the British ^luseum, but mainly for 

 the pedicellarite, and in their structure no reason was found for regarding the 

 West Indian form as specifically different from C. cidaris. As for C. abyssicola 

 I was inclined to regard it as a distinct species.'' 



After having examined a considerable number of specimens from the West 

 Indies, Doctor Clark (The Cidaridse) comes to the conclusion that not only abyssicola 



" hu/tdj Krliinui.l.a, pt. 1, pp. 35, 170-172. 6 Idem, p. 34. 



