4 YERRILL ON THE POLYPS OF THE 



dividing more or less into lobes or branches ; polyps completely retractile into cells, which 

 scarcely rise above the surface of the coenenchyma, and are not armed with prominent 

 spicula ; tissue of the trunk and branches membranous, or more or less coriaceous ; within, 

 cavernous, with tubes running to each branch. 



This genus differs from Ammothea, to which it is closely allied, in not having prominent, 

 verruciform cells ; from Nepkthya, in the same character and in the absence of large navic- 

 ular spicula around the cells ; from Sarcophytum, in its lobed or arborescent mode of growth. 



Alcyonium carneum Agassiz. 



Halcyonium carneum Agassiz, Proc. of the American Association, 1850, p. 209. Alcyonium dlgitatum Stimpson, Synopsis of the 

 Marine Invert, of Grand Menan, p. 7, 1853, (in Smithsonian Contributions, Vol. VI.) 



Base expanded, adhering to rocks or dead shells ; from this arises a more or less cylin- 

 drical, thick, naked trunk, which, after a short distance, divides into several large branches, 

 some of which in their turn give off smaller ones, thus producing a much branched, arbo- 

 rescent form ; branchlets short, somewhat enlarged, and rounded at the ends when con- 

 tracted. 



The cells are small, crowded on the ends of the branchlets, leaving the trunk and prin- 

 cipal branches naked ; polyps when expanded much exsert, nearly half an inch, but capable 

 of entire retraction ; walls and tentacles near their bases strengthened by slender spicula, 

 arranged obliquely in eight double rows, so as to form V-shaped lines, with the angle 

 towards the ends of the tentacles. The spicula are imbedded in the tissues, and do not 

 project beyond the surface. The tentacles are long, tapering, narrow lanceolate, with 

 slender and rather distant marginal lobes. 



Color somewhat variable, but usually delicate flesh color, sometimes tinged with red, and 

 at other times with yellow. The eggs are bright orange, and often visible through the 

 diaphanous walls. 



Range, from Cape Cod to Breton Island, N. S. Generally attached to shells or stones 

 in eight to twenty fathoms ; sometimes at low-water mark. (Coll. Mus. Comp. Zodl.) 



In form and mode of branching this species resembles Gorgonia fiorida of Midler, 1 but 

 the branchlets have a different appearance ; the true affinities of the latter are somewhat 

 uncertain. 



Alcyonium rubiforme Dana. 



Lobularia rubiformis Ehrenberg, Corall. des roth. Meer. (1834). Alcyonium rubiforme Dana, Zoophytes, (1846). 



Low and glomerate, rising from a slightly spreading base; trunk short, dividing into 

 numerous lobes or short branchlets, which are large and rounded at the end, often sub- 

 globular, covered by the polyps ; surface between the cells even and granulous. Polyps 

 in expansion much exsert ; tentacles long, lanceolate, with rather long marginal lobes. 



Color brick red, not diaphanous. 



Range, Newfoundland Banks (Coll Essex Institute) ; northern seas of Europe (Ehren- 

 berg) ; Behring's Straits (Coll. N. Pacific Expl. Exp.). 



1 Zoologia Danica, tab. 137. 



