ECHINOIDEA. I. 



149 



All transitional forms are found between this large form and the small, common form, and the speci- 

 mens in which they are found, agree otherwise exactly with the other specimens, so that there can 

 be no question of interpreting them as a separate species, not even as a separate variety. 



In the triphyllous pedicellarise (PI. XVIII. Fig. 19) the upper edge of the apophysis is most 

 frequently a little arched over the blade, which is somewhat broader than usual; this feature is, how- 

 ever, scarcely to be regarded as a constant, reliable character. -- The sphseridise (PI. XIX. Fig. 31) 

 have some small spines at the end, no grooves. Spicules (PI. XX. Fig. 2) of the common form. - 

 With regard to the colour I may refer to the beautiful figure by Koehler (226. PI. I. Fig. 4). 



Jngolf st. 7 (63 13' N. L. 15 42' W. L. 597 fathoms. Hard clay. 



Sand 



Hard bottom. 



Gray mud with stones. 



Mud with Globigerina. 



Mud. 



From previous collections we have further a few specimens from 65 39' N. L. 28 25' W. L. 

 553 fathoms (Ryder), and from 60 32' N. L. 42o'W. L. 525 fathoms (Wandel). -- It has further been 

 taken by Challenger off Cape Cod and the Bay of Maine, 1350 fathoms (st. 46), one specimen from 

 this locality, by Agassiz referred to Ech. elegans (Chall. Ech. p. 115), proving to be this species. By 

 Caudan it has been taken in the Bay of Biscay. Thus there can be no doubt that this species is 

 found in the archibenthal zone of the whole northern Atlantic; that it has not been mentioned before 

 is, doubtless, not owing to its not having been found there by the earlier expeditions, but to the fact 

 that it has been confounded with other species, elegans and, presumably, especially with nor-uegicus. 

 Otherwise the ridge between Iceland and the Faroe Islands does not form the northern boundary of 

 this species, any more than of Ech. elegans. To be sure only one specimen is known from the Nor- 

 wegian Sea, but this is, moreover, taken on a place, where the bottom temperature was negative 

 (st 176. Norwegian North-Sea Exped. 69 18' N. L,. 14 33' E. L. 536 fathoms. Bottom temperature -=- 0-2). 

 This, however, is certainly an exception; the mentioned station is just at the edge of the large, cold 

 depth of the Norwegian Sea. It is, no doubt, distributed on the smaller depths along the coast of 

 Norway, but in the cold area it certainly is not found. 



') The specimens here noted as doubtful, are young ones, not yet showing the specific characters so distinctly 

 developed, that it can be decided with certainty, whether they belong to this species or to E. af finis (see below p. 152). 



