6 TRANSACTIONS, NATURAL HISTORY SOCIETY OF GLASGOW. 



Pecten pusio (L.). — Valves in great abundance ; showing also 

 much diversity in the form and degree of variability in 

 shape for which this species is noted. " Dead valves fre- 

 quent on the Derry Coast " (Praeger). 



P. varius (L.). — "Of general occurrence around the coasts of 

 Donegal, Derry, Antrim, and Down." Not so frequent as 

 the last species. 



P. opercidaris(L.). — Great numbers of half -grown and beautifully- 

 coloured valves. 



P. tigrinus, Midi. — A few valves. " Single valves at Port rush 

 (Miss Richardson) and Magilligan (Praeger)." 

 *P. tigrinus, var. costata, Jeff. — One large well-marked but 



imperfect valve. Not recorded in Praeger's list. 

 *Mytilus edulis, L. — Frequent, but generally of small size. 



M. edulis, var. incur rata, Penn. — In considerable quantities, 

 attached to drift-wood, etc. 

 *M. edulis, var. pellucida, Penn. — A few examples. 



M. modiolus, L. — Moderately common. 



M. phaseolinus (Phil.).— -Two valves. Not admitted by Brown 

 as sufficiently authenticated to be included among the 

 " Mollusca of the Firth of Clyde, 1878," but well established 

 since. 

 Nticida nucleus (L.). — A few worn valves. 



Pectuncidus glycymeris (L.). — "Thrown up in abundance at 

 Magilligan Strand, but only single valves " (Praeger). 

 This statement holds true also for Port-Stewart. 

 Area tetragona, Poli. — One of the most abundant of all the 

 shells found in the neighbourhood ; valves in countless 

 numbers strew the beach. Regarding the habitat of this 

 species, Jeffreys {Brit. Conch., Vol. II., p. 181) remarks: — 

 " Rocky, stony, and shelly ground on all our coasts and at 

 all depths." But from this comprehensive statement the 

 Clyde estuary must, I fear, be excluded. I have not come 

 across a single record of this species having been obtained 

 in the waters to the north of a line between the Mull of 

 Can tyre and the mouth of Loch Ryan. It has been recorded 

 from Stornoway, 18 fathoms, by M 'Andrew and Forbes; 

 from Iona and Eigg, by Mr. Alexander Somerville ; and 

 from Oban Bay by the Rev. J. E. Somerville, having 



