464 Mr. J. Macgillivray on Marine Zoophytes 



Sertularia Tamarisca. Don-Mouth ; attached to a fragment of Cy- 

 prina Islandica. 



S. abietina. Extremely abundant. 



S. Filicula. Plentifully thrown upon the beach at Don-Mouth, 

 also between that and the harbour. 



S. operculata. Sometimes the cells have one of the lateral teeth 

 abortive or wanting ; in the latter case the remaining tooth is often 

 as long as the mucronated tip, which thus appears bifid. On a small 

 specimen before me presenting the above arrangement, a solitary, 

 somewhat obovate, compressed, truncated, and operculated vesicle 

 has its lateral margin so sinuated as to present three distinct notches. 

 Forming large tufts upon the stem of Luminaria digitata ; abundant. 



S. argentea. Presenting great differences in texture and habit as 

 well as in the form of the cells and vesicles. Thrown plentifully 

 upon the beach. 



S. cupressina. The only specimen which I have seen, and which 

 is almost entirely encrusted with Alcyonidimn parasiticum, exhibits 

 great differences in the form of the cells : the aperture is sometimes 

 patulous, occasionally with two distinct teeth — the typical form ; at 

 other times the orifices are contracted, the cells being somewhat 

 acutely pointed, thus exhibiting one of the characters of S. argentea ; 

 both modes of formation existing upon the same branch. Don- 

 Mouth. 



Tlmiaria Thvia. Branched specimens are by no means rare. 

 Thrown u])on the beach in great abundance ; also brought up by the 

 fishing-lines, attached to stones and shells ; of the latter, especially 

 dead valves of Pecten Islandicus. 



Antennularia antennina. The branched variety, described and 

 figured by Mr. Hassall*, who conjectures its identity with the A. 

 rumosa of Lamark, is here still more common than the normal (un- 

 divided or sparingly branched) state of A. antennina. My specimens 

 agree with Mr. Hassall's one in arising from a single trunk which di- 

 vides into numerous branches, whieh again subdivide ; nor in them 

 have I been able to detect any of " the small tubular cells placed 

 between the larger ones," which are never absent upon the un- 

 branched polypidom. The absence of these cells, together with the 

 peculiar habit, seem to justify Mr. Hassall in considering his A. ra- 

 mosa as a good species. At the same time it would appear that there 

 is another (slightly) branched state f of A. antennina, which is un- 

 questionably a mere accidental variation, being provided with '• the 

 small tubular cells" above alluded to, as I have ascertained by the 

 examination of several specimens. Deep water ; abundant. 



Plumularia falcata. Often much branched, and attaining a large 

 size. Extremely abundant. 



P. pinnaia. My specimens are horn-coloured; they agree with 

 Dr. Johnston's description in every other respect. Upon various co- 

 rallines from deep water ; not rare. 



* Ann. and Mag. of Nat. Hist. vi. p. l(iS. pi. v. 

 t Johnst. Mist, of Brit. Zooph. pi. 15. fig. 2. 



