LEPRALIA. 313 



Isle of Man, Prof. E. Forbes ; Cornwall, Mr. Peach ; dredged 

 off Sana, Mr. Hyndman. 



" Cells ovato-ventricose, punctured, distinct, with a some- 

 what circular aperture, the margin of which is plain and 

 even." (W. Thompson?) The only specimen I have seen of 

 this, I had from Mr. Busk, Greenwich. 

 . 16. LEPRALIA PDNCTATA, W. Sean. 



Hab. On rocks, and sometimes on shells between tide- 

 marks. 



Crust thin, greyish when old; the young cells are whitish, 

 and I have a specimen on an old shell, in which the young 

 white cells are surmounting the old grey crust. It is very 

 common on slaty rock at Saltcoats and at Whiting Bay, 

 Arran. I have never observed denticles on either the upper 

 or the under lip. On some specimens I have, the lips are 

 both thickened, and there is a round tubercle under the 

 inferior lip. In other specimens there is a little sharp loop 

 on each side of the aperture. The tubercles are said to be 

 young ovaries. This pretty species comes very close on 

 some of its neighbours, and it requires considerable powers 

 of discrimination to discern the distinctions. 



17. LEPRALIA ANNULATA, D. L. (Plate XVIII. fig. 68.) 



Hab. On the fronds of Laminaria saccharina, common 



