262 SERTULARIID^. 



North Cape (Sars) : Straits of Belle Isle, abundant between 

 tide-marks (A. S. Packard, jun.) : Nova Scotia (Dawson) : 

 Grand Maiian (teste A. Agassiz) : Massachusetts Bay 

 (Agassiz) : Coast of Belgium (Van Ben.) : common at 

 Naples, from between tide-marks to 1 or 2 fathoms depth, 

 where it often grows on Caulinia oceanica ; the calycles 

 longer and slenderer below than in the northern form 

 (Sars), ? S. gracilis : La Charente inferieure, very common 

 (Beltremieux) : Mossel Bay, South Africa (Krauss) .] 



2. S. GRACILIS, Hassall. 



SERTULARIA PUMILA, \&v.,Johnst. B. Z. 67 : var. (3, F. W. L. Thomas in Johnst, 



B. Z. 469. 

 GRACILIS, Hassall, MS. 



Plate LIU. fig. 2. 



STEM extremely delicate and transparent, filiform, simple, 

 the internodes long, slender, and tapering, often twisted 

 towards the base; HYDROTHEC^E opposite, tubular, the 

 upper half free and divergent, narrowed towards the 

 aperture, which is small and produced into two opposite 

 mucronated points, between which on one side the rim has 

 a slightly angular projection; GONOTHEC^E ovate, smooth, 

 with a very short tubular neck, slightly marginate. 



Height about \ inch. 



THIS species is only about half the size of its ally, S. pumila, 

 and much more delicate in all its parts ; it is also light- 

 coloured and perfectly transparent. The internodes are 

 elongate and slender, and taper off decidedly below, where 

 there is generally a twist or fold. There is little difference 

 in the calycles, except in size. A larger proportion of the 

 length is usually free in gracilis than in pumila ; but this 

 is a variable character. 



The capsule has a much narrower neck,, and is less de- 



