15 



NON-MARINE MOLLUSCA FOUND IN THE PARISH 

 OF MORTEHOE, NORTH DEVON. 



By M. jane LONGSTAFF, F.L.S. 



(Read before the Society, February loth, 1909). 



In 1907 a preliminary list of the non-marine mollusca collected in 

 the parish of Mortehoe was given at the end of my husband's list of 

 the Insecta taken in the district.^ These mollusca were found be- 

 tween September 9th and October loth, 1906, and between August 

 9th and September 30th, 1907. I have revised this list, and am 

 adding the names of specimens found between July i8th and the 

 end of September, 1908, It happened that during both the earlier 

 periods a dry east wind prevailed for a considerable time, especially 

 during September, 1907, and I generally find that land mollusca are 

 extremely shy of showing themselves when the wind is from that 

 quarter. During my collecting time in 1908 every variety of weather 

 was experienced, but the period was chiefly characterised by the 

 prevalence of high winds, sometimes amounting to gales. 



The parish of Mortehoe occupies the north-west corner of Devon- 

 shire, and extends about three-and-a-half miles from north to south, 

 and about three miles from east to west; it contains 4,246 acres, and 

 has a coast-line of about five miles. The north-eastern corner of the 

 parish extending like a horn almost severs the western end of the 

 parish of Ilfracombe ; but, for the purpose of this paper, this, the 

 ancient manor of Warcombe (lying between Lee and Bull Point 

 Lighthouse) is treated as part of Mortehoe ; the same is the case 

 with the slopes of Pickwell Down (in the parish of George Ham) 

 lying above Vention. 



The character of the district cannot be regarded as favourable to 

 the existence of a large number of mollusca, Ijoth on account of its 

 bleakness and its geological structure. A great portion lias a con- 

 siderable elevation, being more than 500 feet above the sea — the 

 highest point attaining 688 feet — and is, therefore, much exposed. 

 The prevalence of slates (Morte) and sandstones (Pickwell), the 

 absence of limestone, and the scarcity of woods, form great hind- 

 rances to many land forms finding suitable habitats, though the 

 extensive dunes along the shore afford a wide range to the sand and 

 sea-loving species. Aquatic species do not fare much better, for 

 there is no river, the streams are very small and mostly swift-flowing, 

 and there are but few stagnant ponds or ditches. 



I Printed for private circulation Nov., T907. 



