A FEW CGELENTERATES OF WOODS HOLL. 97 



zards Bay though I have taken it several times in the deeper 

 waters in the region of Gay Head. 



Eudendrium album. — This species was first described by Nut- 

 ting in 1898. In a "Synopsis of the Hydroids " (Am. Nat., 

 Vol. XXXV., p. 310), I expressed some doubt as to the distinct- 

 ness of Nutting's species. During the present year I have taken 

 two colonies of this little hydroid, which seemed to differ in im- 

 portant points from E. capillare and E. tenue, the species which I 

 had considered probably identical. In comparing these several 

 species, having obtained specimens of E. capillare from Naples, 

 there seems no longer any good reasons for doubting their dis- 

 tinctness. 



Eudendrium carneum. — This species, first described by Clarke, 

 was taken at three different points during the summer, namely, 

 from piles of the docks of the Vineyard Haven Yacht Club ; 

 from fucus off Naushon ; and later dredged off Gay Head. It 

 is not a common species at Woods Holl. In general characters 

 it might easily be mistaken for young colonies of E. ramosum, 

 but may be distinguished usually in the sexually mature stage by 

 its smaller size, rarely exceeding two inches in height and by the 

 flesh red color. 



Hydractinia. — Two points of some interest will be noted con- 

 cerning the local species of Hydractinia, first, the rather interest- 

 ing range of habitat which characterizes it ; and second, some 

 facts bearing on the question of the affinities of the species. 



As is well known the more familiar habitat of the species is the 

 shell inhabited by hermit crabs. So general is this conception 

 on the part of zoologists that it is often given as the distinctive 

 habitat, and that because of this peculiarity it is cited as one of 

 the more common illustrations of symbiosis, and not infrequently 

 pains are taken to show just wherein these creatures sustain 

 essential relations of mutual helpfulness and interdependence. 

 But every careful student of hydroids knows very well that 

 Hydractinia has a range of habitat which would be clearly incom- 

 patible with the foregoing conception of necessary symbiosis. 

 Agassiz long ago pointed out in his original description of the 

 species, H. polyclina, that it was to be found covering rocks in 



