ASHFORD : ON THE DARTS OF BRITISH HELlCIDiE. 197 



was evidently working its way from the interior of the oviduct 

 outwards in the manner described in the first section. The 

 animal containing this fragment had a well-developed dart in its 

 sac. 



Series of examples from Scarborough sent me by Mr. J. W. 

 Taylor, of Leeds, from Somersetshire procured by Mr. J. H. 

 Ponsonby, of London, and from Christchurch have been 

 examined in the months of July, May, and August respectively. 

 In every case without exception when the mouth of the shell was 

 formed a dart was present. That it is however sometimes lost 

 in conflict is proved by the case of the free dart in the oviduct 

 above referred to. 



Fig. 2 is from a specimen from Somerset, fig. 4 from Scar- 

 borough, the rest from Christchurch examples. 



1 1. Helix lapicida L., pi. viii., figs. 5 — 7. Dart-sac slender, 

 cylindrical with a slightly enlarged and rounded end ; 

 pearly-white or greyish-white, semi-transparent. Dart 

 of the same type as in H. arbustorum ; shaft extremely 

 slender, round, curved ; head lanceolate, much com- 

 pressed but not broad, with sharp margins ; base 

 gradually expanded ; annulus absent. Length 3^ to 

 4 mm. 



The dart-sac (figs. 5 and 6) appears to be long on account 

 of its narrowness ; it is decidedly less clavate than that of the 

 species last described and is white at all ages. When held to the 

 light or placed in water a thin dark line shows the position of 

 the enclosed dart. I have found it very constant in shape, yet 

 various writers have described it in very different terms. Dr. 

 Lister, who calls it pyriformis, figures it nevertheless nearly 

 cylindrical (Exer. Anat., tab. 5, fig. 4). 



Accompanying the dart-sac and disposed as in H. arbustorum 

 are two simple mucous glands from 9 to 1 5 mm. long (figs. 5 and 

 6), but they are more slender and vermiform and less stiif than 

 in the last, and are widest near the bluntly-rounded extremities. 

 No instance of terminal cleavage has come under my notice. 

 H. Fisana, arbustorum, and lapicida are the only British species 

 with two glands normally simple. 



