196 ASHFORD : ON THE DARTS OF BRITISH HELICID^E. 



In the dart of this species (fig. 3) we meet with a new tj^pe 

 of form essentially distinct from all preceding it, unless we incline 

 to consider the dart oi Zonites excavatus with its slightly flattened 

 head as an obscure example of the same type. A slender, curved 

 shaft opens out below into a large, long, funnel-shaped base, with 

 its inner line of contour more conspicuously curved than the 

 outer, and expands above — usually with some abruptness — into 

 a substantial, compressed, lanceolate head, the blunt edges of 

 which lie quite or nearly in the plane of curvature. As these 

 edges converge to the transparent, not very sharp point more 

 gradually than they diverge from the neck, the greatest width of 

 the head is below its centre. Between a half and a third of the 

 entire length of the weapon is occupied with this strongly-marked 

 adjunct. Paasch compares it to a myrtle leaf, Verloren to a 

 spatula, Schmidt to a lancet. The central cavity of the dart is 

 continued through the inferior portion of the head, and some- 

 times extends far into the upper half, but is there contracted into 

 the merest perforation. 



Modifications of form are numerous but slight in amount, 

 and altogether unimportant. They have reference to the relative 

 proportion of head, neck and base, to the degree of curvature 

 and the like. 



I have never met with the dart in an early stage of formation 

 and can conjecture its appearance only from analogy. When 

 not quite mature (fig. 4) the head is shorter, occupying less than 

 one-third of the total length, rather flatter, moie acutely edged, 

 more sharply pointed, having its greatest width nearer its middle, 

 the base is less inflated and the whole weapon less substantial. 

 The figure accompanying Mr. Taylor's Life History of Helix 

 arhustoriim in the Journal of Conchology, vol. iii., pi. i., fig. da 

 represents a dart not fully matured. 



In one dissection of this species I found a broken dart- 

 wanting the base — lodged in the wall of the oviduct, rather more 

 than half the head protruding into the intervisceral space, if 

 space it may be called where everything is closely packed. It 



J.C, iv., July, 1884. 



