28 MABINE FAUNA OF ST. ANDREWS. 



Genus Sektulawa, Linn. 



Sertularia pumila, L. ; Hincks, Brit. II. Z. vol. i. p. 260. 



This is the common Sertulaiian under Btones in rock-pools 

 at and near low-water mark at St. Andrews ; hut it is less 

 luxuriant than on the Fuci of the western coasts. It forms 

 a miniature forest on the under surface of the stones in quiet 

 places, and is a favourite haunt of Eolia mridis and other 

 Nudibranchs. It presents the peculiarity in such situations 

 that the stem is not always contracted above the lndrnthecae, 

 but not unfrequently these follow each other without the con- 

 striction. In some preserved specimens the hydrothecse con- 

 tained a number of large nucleated cells, having apparently a 

 thickened and regularly crenated cell-wall ; these cells varied 

 in size; and some also occurred in the centre of the stem. 



Sertularia operculala, L. ; Hincks, Brit. II. 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 filicula, Ellis and Solander ; Hincks, Brit. II. Z. 

 vol. i. p. 264. 



This, perhaps, is the most abundant Sertularian next to 

 S. abietinairom 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. II. Z. vol. i. p. 266. 



Very common, and occasionally reaching the height of 

 !t inches; fine tufts occur on MytiluB modiolus. This species 

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

 zoophytes, calcareous corallines, Spirorbis, Alcijonidmm. 

 <'i>pj>iiii(t, &c. From its attachment to living mollusca 

 {Anomia and others) it is not unfrequently swallowed by the 

 cod. 



