l6 ECHINOIDEA. I. 



also really bihamate spicules are found, although only in small numbers. The sphseridise (PI. XX. 

 Figs. 13, 18) quite smooth or a little thorny, sometimes also a little grooved. 



By the Ingolf -Expedition it has been taken on the following stations: 



St. 2 (63 04' N. L. 9 22' W. L. 262 fins. Clay, gravel. Bottom temp. 5 9). 2 spec. 



It is very widely distributed being found in all the arctic seas, and passing far to the south, 

 both in the Atlantic (to the English Channel and Massachusetts Bay) and in the Pacific (to Vancouver 

 Island and Korea). It is a littoral form, but goes rather deep; by the Ingolf it has been taken on 

 a depth of 420 fathoms, and V err ill even mentions it from 640 fathoms (426. p. 540.) 



It is no wonder that a so widely distributed species is very varying; a whole series of &species» 

 has also been established on more or less marked forms of it. I completely agree with Agassiz, 

 Bell, a. o. that it is quite impossible to keep the forms described under the name of pallidas, granu- 

 laris, piciiis, and carnostis 1 ) distinct from the typical drebachiensis or from each other. Forms are 

 not rarely found, to be sure, which may easily be referred to these forms, but most frequently such a 

 referring will be impossible. I have examined several hundreds of specimens and found all possible 

 transitional forms. Marked local forms seem not to be found; but as a general thing it may be said 

 that in the Danish seas a more long-spined form is the most common one, at the Faroe Islands a 

 form with numerous short, strong spines and almost without spicules in the globiferous pedicellariae 

 seems to be predominant (most nearly the form granular is); the Icelandic and East-Greenland speci- 

 mens seem upon the whole to have very numerous spicules in the globiferous pedicellariae, and the 

 Pacific specimens may often be referred to the form carnosus; quite typical drebachiensis are, however, 

 found so far down as Korea (after specimens in the museum of Copenhagen). These forms may 

 so far be kept up as distinct varieties, but I do not see that we gain anything by it. Most specimens 

 it will certainly be impossible to refer to any decided one of these varieties, and the separate varieties 

 may often be found together. Neither can any difference be pointed out between the forms from 

 shallow water and those from deep water. 



Also the colour is very varying; most common is a grayish white or a somewhat greenish colour, 



') With regard to Sir. cliloroceutroius see above p. 120. 



