NOTES ON THE MARINE MOLLUSCA OF PORT STEWART. 6 



list of species. To their perseverance and industry I am greatly 

 indebted for any completeness which this shore list presents. 



A few days' research soon revealed the fact that certain stretches 

 of the sandy beach yielded certain shells in abundance which were 

 comparatively scarce elsewhere. Of course there is always the 

 difference of habitat between the i-ock-lo^dng species (such as 

 Patella, Littorina, and Purpura), and those specially addicted to 

 sand, such as Mya, Tellina, Cardium, and Venus. But, in addition 

 to these broad distinctions, it was curious to note how Cyprcea 

 europcca occurred in very large numbers near Rock House, but was 

 very much scarcer as one proceeded west. Indeed, it might be 

 possible roughly to space out the shore according to its pre- 

 dominant shells, although it must always be borne in mind that 

 dovetailing of the groups was inevitable to a certain extent. 

 Proceeding westward then, the order of prevailing species was 

 something like this : — On the gravel bank near Rock House, 

 Cyprcea europcea, Trochiis cinerarius, and Pleurotoma tnrricula. 

 At the little sandy bay known as the •' Ladies' Batliing Place," 

 by far the most abundant shell was Donax vittatus. Beyond the 

 last rocky point, till the River Bann is reached, the sandy beach 

 might be spaced out into portions where the predominant types 

 are respectively : — Montacuta, Helcion pelhicidum and its var. 

 Icevis, Venus, Solen, Capulus and Fissurella, Mactra, then a 

 small stretch of Cypraa, followed by a portion of the beach on 

 both sides of the old stranded wreck on which alone Actceon was 

 procured. This is but a rough division, but the absence or presence 

 of particular shells from certain portions of the beach was so 

 marked, that one instinctively came to associate certain strips of 

 sand wdth certain corresponding molluscs. 



There has not been such exhaustive conchological work carried 

 on in Ireland as has been the case with some parts of Scotland, 

 and notably the Clyde area. But the number of workers is 

 increasing, and they are animated with great enthusiasm. Most 

 of their results find publication in the pages of the Irish 

 Naturalist, but there is one exhaustive treatise on "The Marine 

 Shells of North Ireland." which stands out to this day as the most 

 complete work on the subject. It is compiled by the Keeper of 

 - the Royal National Library in Dublin, Mr. Robert Lloyd Praeger. 

 On my finding out the molluscan richness of the locality, I wrote 



