30 
Proceedings of the Royal Society of Edinburgh. [Sess. 
In discussing Sertularelia plectilis , following, I have given the reasons 
which lead me to regard the specimens identified by Yanhoffen (1910) 
as Sertularelia glacialis, as belonging not to this species but to Sertula- 
rella plectilis. There is little to choose between the characters of the 
trophosomes of Sertularelia glacialis and of Sertularelia subdichotoma, 
Kirchenpauer. 
Sertularelia plectilis , Hickson and Gravely. 
Sertularelia plectilis, Hickson and Gravely, 1907, p. 20, pi. iii. fig. 21. 
Sertularelia glacialis , Yanhoffen, 1910, p. 325, fig. 40; but not of Jaderholm, 
1904, p. 9, and 1905, p. 26, pi. x. figs. 3-7. 
Colonies associated in the inextricable matted tangle which characterises 
this species have been found at several stations. At the base of each 
Fig. 8. — Part of branch of Sertularelia plectilis, 
with male gonangium. x 50. 
Fig. 9. — Part of branch of Sertularelia plectilis , 
with female gonangium. x 50. 
branch there is a single twist, and rarely short sections of stem or branches 
bear loose corrugations. 
The trophosome of our specimens agrees with that described by Hickson 
and Gravely from Ross Island, but the hydrothecse of the latter are 
slightly larger. It also agrees very closely with the descriptions and figures 
by Yanhoffen of a species which, while admitting its identity with that of 
Hickson and Gravely, that author ascribes to Sertularelia glacialis, Jader- 
holm ; and the dimensions of parts are similar to those of Yanhoffen’s 
examples. Mature gonangia were not observed by Hickson and Gravely, 
but Yanhoffen has described and figured an example, the sex of which is 
not mentioned. On our specimens both male and female gonangia occur 
