SERTULARIA CUPRESSINA. 271 



" the Sea-cypress" is very expressive of the peculiarities in 

 its mode of growth and the gracefulness of its habit. 



S. cupressina is much larger than its ally, with a thicker 

 main stem and longer and much narrower branches, which 

 are less frequently subdivided and less crowded together. 

 They are gracefully arched or drooping, and of a delicate 

 pearly whiteness, offering a striking contrast to the stout 

 and deep-coloured and very conspicuous stem from which 

 they spring. The branches of S. argentea, on the con- 

 trary, are broad, compact, rigid, and dark- coloured, forming 

 a dense clothing, and giving a bushy appearance to the 

 shoot. Another salient feature of S. cupressina is its 

 much produced, spire-like apex. The branches begin to 

 decrease in size at a considerable distance below the top, 

 and from this point the shoot rapidly tapers away, often 

 running out into a bare and branchless extremity. The 

 calycles of the two species are also sufficiently distinct in 

 form. Those of the cupressina are appressed, tubular, not 

 much narrowed or divergent above, with a bilabiate mouth ; 

 while those of argentea are shorter, swollen below, tapering 

 upwards, with the aperture bent, sharply pointed at one 

 side, and oblique. 



There are commonly six calycles to an internode in this 

 species ; but the number varies. 



The polypites have about 20 tentacles, are long and 

 slender, and extend very far beyond the orifice of the 

 calycles. 



The capsules, which when mature are crowned by their 

 large marsupial sacs, are produced in rows along the upper- 

 side of the pinnules, that seem to bend beneath their 

 load. They contain about six planules. 



Hab. This species seems to be less abundant than the 

 preceding, though very widely distributed in deep water. 

 South Devon and Cornwall (T. H.): Dorset (Forbes): very 



