ECHINOIDEA. I. 



l8l 



esculentus var. tentdspiria (p. 162), and so it gets tlie uame of Echinus tenuispinus n. sp. It is, as 



seen by Norman, closely allied to csculcuhis, with which it agrees in the most important characters: 



primary tubercle onl\- on every other ambulacral plate, and spines on the biiccal piates; it is easily 



distinguished from the latter b}- having far fewer 



tubercles, among which the primary series are ver\- 



distinct, and by its white colonr — csculoitus seems 



always to keep the colonr in spirit. I am decidedh- of 



opinion that it mnst be regarded as an independent 



species, not only as a variety of csculoitus. It differs 



cousiderably as to habitns from this species, among 



whose forms I know 110 specimens with which it ma\ 



be confonnded. What I, above (p. 162), have interpreted 



as var. tenuispinus., is a pecnliar form with short, fine 



.spines, but with the usnal colonr of the test (from the 



Faroe Islands); accordingly it is not identical with 



Norm an' s var. tenuispinus. 



« Strongyloccntrotus , lividus (p. 165) is by S 1 n i t e r (37 1 ) 

 mentioned from Dogger Bank — it is .S7/'. drobacliicnsis. 



Finally I shall call attention to the faet that no single regular Echinid belongs to the large 

 cold depth north of Iceland. The account of the geographical distribution must otherwise be put off 

 until the whole Echinid-material has been e.xamined. 



Fig. 12. Echinus ienuispinus n. sp. Natural size. 

 (From a photograph.) 



