17 



and separated from the stem by a joint, short with everted 

 apertures; vesicles scattered. Polypes hydraforoi. 



* Cells distinctly alternate. 



GREAT TOOTH CORALLINE. S. Polyzonias. Erect, 

 subflexuous ; cells ovate, with a wide somewhat uneven 

 aperture ; vesicles obovate, wrinkled across, the orifice 

 contracted and plain. 



Corallina minus ramosa, alterna vice denticulata. Muscus 

 marinus denticulatus minor, denticellis alterais ; iiaii 

 Synop., vol. 1, p. 35, no. 13. Great Tooth Coralline, Ellis 1 

 Coral., pi. 5, pi. 2, fig. a A., and pi. 38, fig. 1 A; Sertularia, 

 polyzonias, Ellis and Solander's ZoopU., p. 37, no. 3. 

 Turton's Lin. vol, 4, p. 683. Blumenbach's Man., p. 273. 

 Stewart's Elem., vol. 2, p. 447. Fleming's Brit. An., p. 542. 

 Templetou in Mag. Nat. Hist., vol. 9, p. 468. Johnston's 

 Brit. Zooph., p. 122, pi. 8, figs. 1, 2, and 3. Lamouroux's 

 Cor. Flex., p. 190. 



Hab. On fuci beyond low water mark, on stones and 

 shells from deep water; common. Parasitical on Aicyoniuin 

 digitatum, or dead man's hands, and other corallines; very 

 common, from the Rame Head to the Lizard, and ten leagues 

 from the shore. 



There are two varieties of this species, both alike com- 

 mon ; the first, where the stem is composed of a single fibre 

 and sparingly branched, rarely exceeding two inches in 

 height ; the second, where the stem is composed of a 

 number of tubes twisted on each other and growing to 

 the height of six inches. In the last variety, the polypidom 

 is erect, rigid, and rooted, with tubular fibres which are 

 closely matted together. I have a fine specimen from deep 

 water, growing in a large tuft, ten inches in height. 



The following has also been considered a varity of this 

 species, but is now allowed to be distinct. 



ELLIS' CORALLINE. S. Ellisii. Ciimbing, flexuous ; 

 the cells urceolate, bulged at the base, with a four toothed 

 rim ; vesicles with the opening four-toothed. 



Ellis' Corallines, p. 6, pi. 2, fig. b, B. Sertularia Ellisii, 

 Johnston's Brit, Zooph, p. 123. 



Hab. On Ascidia with other corallines ; rather rare. 



This can be distinguished from the last by the stem being 

 more zigzag, the mouth of the cell more decidedly four- 

 toothed, and the whole more slender and climbing. The 

 vesicles are vasiform and surrounded with prominent bands, 

 which give them a remarkable appearence. 



