MOLLUSCOIDA. 55 



after storms, and also under stones between tide-marks. 

 Evinces considerable and spasmodic muscular contractions. 



Ascidia sordida, Aid. & Hanc. 



[Plate IX. figs. 1 & 2.] 



Very plentiful in the deeper water attached to stones, shells, 

 sticks, and seaweeds. One has placed itself on the anterior 

 end of an empty tube of Pectinaria belgica and quite filled it up 

 (Plate IX. figs. 1 & 2). An elongated (club-shaped) variety 

 is not uncommon. 



Ascidia depressa, Aid. & Hanc. 



Not uncommon on the under surfaces of large stones in tide- 

 pools. In November specimens are often loaded with a 

 pinkish-white creamy fluid, which appears to be made up chiefly 

 of ova. The cellular border of each ovum is faintly greenish 

 by transmitted light. 



Genus Molgula, E. Forbes. 

 Molgula arenosa, Aid. & Hanc. ; Alder, op. cit. p. 160. 

 Abundant in deep water, and in the stomach of the cod and 

 haddock. 



Genus Cynthia, Sav. 

 Cynthia, n. sp. 

 A nodulated Ascidian like a raspberry or small bramble 

 occurred on the West Sands after a storm. Mr. Alder stated 

 that it was not C. morus, but a species unknown to him. 



Cynthia grossularia, Van Beneden ; F. & H. Brit. Moll. 

 i. p. 40. 



Very common on the roofs of rocky ledges, between tide- 

 marks, where it becomes incrusted by many parasites. The 

 development of this species is easily observed. 



