IDONTRIBUTIONS TO THE BRITISH FAUNA. 251 



9. Flustra EUisii, 

 PL xvii. fig. 1. nat. size, fig. 2. mag., fig. 3. side view. 



Substance firm, brittle, and gritty when dry. 

 jColour yellowish-white. The base consists of 

 small horny tubuli, by which it is fixed. These 

 tubuli unite, and form narrow linear leaves dicho- 

 tomously branched. The branches are somewhat 

 rounded and celliferous above. The under side 

 is carinated, and destitute of cells. The tubuli 

 or fibres of which the substance is composed on 

 the under side, can be distinctly seen diverging 

 from the keel towards the edge of the leaf, and 

 forming two small denticles and a bristle on the 

 upper side of each lateral cell. These bristles are 

 about three times the length of the diameter of 

 the branches, and are finely denticulated on one 

 side. The cells are oval, and obliquely disposed 

 in two or three rows. 



This Flustra was brought up by the cod-lines 

 from a hundred fathoms water, off Stenhouse, in the 

 parish of Northmavine, Zetland, in July 1 808. It 

 was growing on an aged specimen of Eschara cer- 

 mcornis, in company with Retepora cellulosa. 



As this Flustra appears to be a new species, I 

 have named it in honour of Mr Ellis, that able 

 investigator of the natural history of Zoophytes, 

 whose works exhibit a striking example of perse» 

 yering industry, and accurate investigation. 



