28 



by its having great intervals between the pinna*, and the cells 



not having their apertures everted as in the following species ; 



and beside this the aperture here is always pointed. 



SEA SPLEENWORT, or POLYPODY. Th. Arti- 



culata. Polypidom plumous ; stem of equal thickness 



throughout; pinna? stout, closely arranged, alternate; cells 



biserial on the pinna? and stem ; imbedded, closely arranged, 



alternate; vesieles elliptical. 



Sea Spleenwort or Polvbody, Ellis' Coral., p. 11, no. 10, 

 pi. 6, fig. a A. Sertularia Lonchitis, Ellis and Solander's 

 Zooph., p. 42. Sertularia Lichenastrum, Turton's Liu., 

 vol. 4, p. 683. Stewart's Elem., vol. 2, p. 447. Thuiaria 

 Articulata, Fleming's Brit., An., p. 545. Johnston's Brit., 

 Zooph., p. 138, pi. 15, fig. 3 and 4. 



Hah. On the back of the corwich crab, (Maia Verrucosa) 

 Polperro, Goran-haven on a stone from deep water, 

 Mr. Peach. It is not at all rare to meet with fragments, with 

 all or most of the pinnae gone, but it is very rare to meet 

 with a good specimen. 



This species varies in height from two to four inches, but 

 one specimen which Mr. Peach procured from Torbay, 

 Devonshire, measured five inches and a quarter. When 

 living it is of a beautiful pellucid amber colour, which 

 becomes duller in dying. The stem is stout, of nearly equal 

 thickness throughout, and divided very irregularly by im- 

 perfect septa. The pinnse, which are closely arranged, arise 

 from the stem in an alternate manner, and are confined to 

 its upper part ; those on the lower portions are thrown off 

 in regular succession, as the polypidom advances in growth. 

 The cells are biserial, on the pinnae and trunk, adnate, closely 

 arranged, alternate; their apertures are even, everted and 

 not prominent The vesicles arise from each side of the 

 pinna?, but most numerously from the upper; they are 

 oviform, sub-pedunculated, with contracted terminal aper- 

 tures. 



Fragments of this species are frequently found on the 

 backs of corwich crabs in the spring and summer, when 

 they first move from their hybernating retreat. On shells 

 and stones, eight or ten leagues from land in about fifty 

 fathoms water, after some weeks of continued fine weather, 

 they have been found in a very perfect state. 



AKTENXULARIA. Lamarck. 

 Generic Character: Plant like, horny, simple or branched 

 irregularly, the shoots fistular, jointed, clothed with hair- 

 like verticillate branchlets; cells small, sessile, cam- 

 panulatc, unilateral; vesicles scattered and unilateral. 

 Polypes bydraform. 



