CHASTER AND HEATHCOTE : MOLLUSCA OF OBAN. 305 



A. patelliformis, L, Bo\.\\ patellt/ormis ^nd striata, Lev. occur 

 in the dredgings. We are inclined to regard these as 

 varieties only of the typical species. 



Ostrea edulis, L. A few valves dredged off Maiden Island. 



Lima hians, Gmel. Fresh valves dredged in the Sound of 

 Mull and off Maiden Island. 



L. loscombii, Sow. Valves only taken with those of the last 

 species. 



L. elliptica, Jeff. Two living specimens and a large number 

 of valves dredged off Maiden Island. The record of Z. 

 subauiiculata given by Forbes is, of course, valueless, as 

 he united that species with the present. 



Pecten maxim us, L. Two adults dredged off Maiden Island, 

 with a few prettily marked young shells. 



P. varius, L. \^P. niveus A.M.N. ; R.D.D. MS.]. The type 

 is conspicuously absent. With regard to the niveus form 

 the writers are at variance, one considering that it is fully 

 entitled to specific rank, whilst in the opinion of the other 

 the arguments adduced by Jeffreys are too weighty to be 

 lightly discarded. It seems that it ought to be possible to 

 finally settle the question by tracing the species from Oban 

 to Loch Fyne, where, as in the whole Clyde district, the 

 type only occurs, and by noting the presence or absence of 

 intermediate forms. The var. nivea is fairly common in 

 the strait between Fraoich and Kerrera, moored by a 

 strong byssus to the surface of the Lanmiaria fronds. The 

 largest specimens obtained measure 63 mm. in length. 

 The large ones are generally more or less Cliona-\ioxtdi. 

 Small examples were found attached to stones on Fraoich 

 Island and on the shore south of Oban. 



P. tigrinus, Miill. [A.M.N.; frequent, all ages, on Laviinaria 

 and free, R D.D. MS.]. Dredged sparingly though generally 

 distributed. Most of them belong to the var. costata, Jeff 



