ASHFORD : ON THE DARTS OF BRITISH HELICID^. 1 99 



A mounted dart now before me is represented in fig. 9, 

 enlarged 100 diameters. It seems to be an extremely attenu- 

 ated cone without blades or annulus. Whether this be the 

 form of a mature weapon or not I must leave. 



Dr. Goldfuss mentions the dart in his catalogue of Mol- 

 lusca found in the Rhine-province and Westphalia, 1855, and 

 I have met with no earlier reference. That author remarks 

 ".^ pidchella and H. costata have a comparatively long, straight 

 dart." 



The figures are from a specimen taken near Christchurch. 



13. Helix aspersa Mliller, pi. viii. figs. 10 — 18. Dart-sac 



broadly clavate or subpyriform, sometimes indistinctly 



ringed at the neck, white at all ages. Dart curved, 



furnished with four thin, sharp-edged blades, all 



equally salient or two broader than the others ; neck 



long ; base conically expanded ; annulus of 14 to 18 



rods. Length 8 to 9 mm. 



Both coats of the ample, firm, simple sac (fig. 10) are 



white but not quite opaque, for the position of the enclosed 



dart is indicated by transmitted light. The outer envelope is 



thick and tough, the inner one more spongy. In H. 7ievioralis 



the core of the tubercle supporting the dart is violet, in the 



present species opaque white. 



Conspicuous by their small size in relation to the animal 

 and by their multifid habit, the mucous glands form two bushy 

 tufts not extending far beyond the end of the dart-sac. In this 

 country they vary from 9 to 12 mm. in length, but naturally 

 attain a greater length in regions more favourable to the 

 development of large shells. The short, thick stalk divides 

 into 2 to 5 branches, each supporting a ven,' variable number 

 of slender vermiform bluntly-terminated branchlets, white with 

 a tinge of blue. Scarcely two individuals are alike in the 

 number of terminals or mode of subdivision, and the companion 

 glands of the same animal differ in the former respect within 

 narrow numerical limits. Adults have usually from 20 to 30 



