MOLLUSCOIDA. 45 



MemhraniporaLacroixii, Sav.; Busk, Catal. p. 60, pi. 69, 

 pi. 104. f. 1. 



On the inner surface of a valve of Cyprina islandica from 

 deep water. 



Membranipora spitiifera, Johnst. ; Alder, Catal. Zooph. p. 53, 



pi. 8. f. 2, 2 a. 



Abundant on the under surface of stones between tide- 

 marks. 



Membranipora Dumerilliiy Aud. ; Alder, Catal. Zooph. p. 56, 



pi. 8. f. 5. 



Not uncommon on bivalves from deep water. As Mr. Alder 

 observes, it may occasionally be seen in company with M. 

 Fhmingii. 



Membranipora unicornis, Flem. ; Alder, Catal. Zooph. p. 56, 

 pi. 8. f. 6. 



On bivalves from deep water ; not very common. 



Membranipora craticula, Alder ; Catal. Zooph. p. 54, pi. 8. f. 3. 

 Occasionally in deep water. 



Genus Flustrella, Gray. 



Flustrella hispida, Fab. ; Johnst. Brit. Zooph. p. 363, 

 pi. 66. f. 5. 



Abundant on the stems of Fuci and other seaweeds, and on 

 stones between tide-marks. 



Genus Lepealia, Johnst. 



Lepralia Brongniartii, Aud. ; Busk, Catal. p. 65, 

 pi. 81. f. 1-5. 



Kather plentiful on laminarian roots tlu-own on shore after 

 storms. Often forms a basis for other growths, and may be 

 seen on their under sm-face when detached from seaweed or 

 rock. 



