,, ECHIXOIDEA. I. 



pletely separated series. Towards the sucking disk they become larger and more thorny, at last 

 highly complicate; the arcuate ground-form may, however, always be distinguished. They may here 

 join on both sides, so that the foot is completely mailed. 



Together with Agassiz, End wig, Koehler, Bell, a. o. I think it unquestionable that the 

 Mediterranean form C. hystrix Lamk. is identical with this species. The only definite character found 

 by Philippi and Sars for distinguishing between this latter and D. papilla fa is the fact that in the 

 latter there are 16 — 18 raised, dentate, longitudinal ridges on the spines, in C. hystrix only about 12. 

 As, however, in the same individual, as well of the northern form as of the Mediterranean one, some 

 spines may be found with 12 — 13 ridges, and others with 16 — 17 such, this character is useless. It 

 may be possible that the spines in the Mediterranean form are somewhat longer and slenderer than 

 in the northern form; the tridentate pedicellarise seem also to be somewhat more dentate in the edge 

 than those of the northern form. I think that it may at most be regarded as an only little marked 

 variety of D. papillata. 



Dorocidaris abyssicola Ag. has by Agassiz himself been referred to D. papillata as a synonym; 

 whether it ma}* possibly be kept as a separate species, or at least a variety I am not able to decide 

 from my material (one specimen from U. S. Fish Comm., and one from Mus. Comp. Zool); it might, 

 however, seem as if the small globiferous pedieellarise might yield a character tending this way 

 (PI. IX. Fig. 14). -- In Revision of Echini p. 256 Agassiz mentions a variety of Doroc. papillata with 

 slender, highly dentate spines. Also Rathbun (op. cit. p. 611) mentions this variety. Our museum 

 has received some specimens of this form from U. S. National Museum. A closer examination shows 

 that it has nothing to do with D. papillata, it is Cidaris a /finis, or a variety of this species. 



Dorocidaris papillata is spread over the northern Atlantic and the Mediterranean; for the 

 present it cannot be said how far south it reaches, nor can it be decided to how great a depth it is 

 found. As there has proved to be a great uncertainty in the earlier determinations of Cidarids, and 

 as especially a widely different species, even from a quite different genus, viz. Cidaris a/finis, has gene- 

 rally been confounded with D. papillata, all the statements in literature as to its occurrence are not to be 

 relied on with certainty. Only so much may be said of its distribution in the Atlantic that it is found 

 along the coasts of Norway on depths from 100 — 200 fathoms, at the Shetland Islands, but not farther 

 south in the North Sea, south of Iceland (Tngolf), at the Atlantic coasts of Great Britain, and pre- 

 sumably at the coasts over the whole of the North Atlantic, as well at the European side as at the 

 American side (Florida). On the other hand it is not found in the territories of the North Atlantic 

 where the bottom temperature is negative (the cold area ). In Bell's Catalogue the depth is given 

 to from o — 874 fathoms. This is scarcely correct; it seems to be found on no smaller depth than 

 30 — 40 fathoms. Wyv. Thomson (op. cit. p. 725) states that he has some small specimens from 

 ca. 1000 fathoms. D. papillata is no abyssal form, it seems mostly to be found at a depth of some 

 hundreds of fathoms. Its having pelagic larvae of the typical Plutais-iorm seems also to agree with 

 the fact that it does not live on the very great depths. 



D. papillata has been taken by «Ingolf on st. 1 (62 c 30' N. Lat, 8°2i'W. L., 142 fathoms; bottom 

 temperature f 8), 1 specimen, and st. 54 (63 08' N. Lat, 15 40' W. E, 691 fathoms; bottom tempera- 

 ture 4 2), 1 specimen. 



