350 BIOLOGICAL SURVEY OF 



This form is not parasitic in the true sense, but appears to 

 grow only on the surfaces of other animals, especially on 

 rounded stems, and I have never observed it on algae. The 

 zoarium is covered with a coat of earthy matter to such an 

 extent that it is difficult to study the zooecia except at the 

 extreme edge of the colony. The frontal area of the zooecium 

 is smooth, with a row of small marginal papillae. The septa 

 between the zooecia are very distinct in the young, but soon 

 the colony appears as a grayish layer with small depressed 

 areas which represent the middle of the zooecia. 



Alcyonidium gelatinosum (Linnaeus), 1766—1768. (Os- 

 burn, 1912, p. 252, references ; Whiteaves, 1901, p. 114, Gulf 

 of St. Lawrence.) Rare, taken only at shore stations 4 and 14 

 and at dredging station 21, all in inner waters of the region. 

 It is a circumpolar species, taken at numerous points in the 

 Arctic Ocean, southward to the Mediterranean, to southern 

 New England, and to British Columbia on the Pacific coast. 



The zoarium is erect, simple or branching, very irregular 

 in form, the branches nodulose and usually roughly subcylin- 

 drical. The branches are usually a quarter of an inch or 

 more in diameter, the central portion semitransparent, gel- 

 atinous, and the zooecia packed closely together in the outer 

 layer. The orifices of the zooecia are in low papillae, and 

 other small and low papillae are often present. 



Alcyoxidium mamillatum Alder, 1857. Not uncommon on 

 shells, stones, and stems ; noted at five shore stations and nine 

 dredging stations. It is probably circumpolar in distribution, 

 as it has been recorded from the Kara Sea westward to the 

 Dolphin and Union Strait, Arctic Canada. Hincks noted its 

 presence in deep water otf the coast of England, but in Ameri- 

 can waters it has not been recorded south of Greenland, except 

 at Richmond Gulf, east side of Hudson Bay. Its presence in 

 such numbers at Mt. Desert Island indicates that it is not a 

 mere straggler in this region, and it will probably be found 

 along the coasts of Nova Scotia, Newfoundland, and Labrador. 



The zoarium usually encrusts stems, forming a coarse, 

 brownish layer from which arise tall, stout, transversely wrin- 

 kled papillae, in the tips of which are located the apertures. 



