Dr. AV. C. M'Intosh on the Zoophytes of St. Andrews. 213 



Sertularia operculata^ L. ; Hiucks, Brit. H. Z. vol. i. p. 263. 



Not uncommon ; on seaweeds at and beyond low-water 

 mark, but chiefly procured on the West Sands after storms. 

 Its comparative scarcity is in marked contrast with its profu- 

 sion on our western coasts, where almost every laminarian root 

 and stalk are clothed with dense tufts. 



Sertularia filicida^ Ellis and Solander ; Hincks, Brit. H. Z. 

 vol. i. p. 264. 



This, perhaps, is the most abundant Sertularian next to 

 S. abietina from deep water. Dried specimens, when carefully 

 laid out, show a somewhat rectangular arrangement of their 

 terminal branches. Good examples have also been procured 

 from the stomach of the cod. 



Sertularia abietina^ L. ; Hincks, Brit. H. Z. vol. i. p. 266. 

 Yeiy common ; and occasionally reaching the height of 

 9 inches ; fine tufts occur on Mytilus modiolus. This species 

 is a favourite seat of many parasites, such as other hydroid 

 zoophytes, calcareous corallines, Sjnrorhis^ Alcyonidium^ 

 Coppinia, &c. From its attachment to living mollusca 

 (Anomia and others) it is not unfi'equently swallowed by the 

 cod. 



Sertularia argentea, Ellis and Solander ; Hincks, Brit. H. Z. 

 vol. i. p. 268. 



Not common ; from the deep-sea lines of the fishermen. 

 This seems to be a form more characteristic of our southern 

 shores. 



Sertularia cupressina, L. ; Hincks, Brit. H. Z. vol. i. p. 270. 



Very plentiful in the coralline region, and sometimes reaching 

 the length of 18 inches. Besides the ordinary form there are 

 two branched varieties. In the first, numerous secondary poly- 

 paries spring from the ordinary dichotomous branches, each 

 twig so burdened being very little thicker than the ordinary 

 forms, and bearing in the usual manner for some distance the 

 hydrothecffi, which gradually become obsolete ; this secondary 

 trunk assumes considerable dimensions, with jointed stem and 

 dichotomous branches, like an independent specimen. In the 

 other variety the main stem itself splits into two divisions, or 

 the secondary trunks throughout are directly connected there- 

 with. 



Sertularia fusca, Johust. ; Hincks, Brit. H. Z. vol. i. p. 272. 

 A single fine specimen only has yet been procured, in the 



