ASHFORD : ON THE DARTS OF BRITISH HELICID^. Ill 



the sac, but near the commencement of the reflected part (fig. 

 9). The white shaft and dilated base are clearly seen through 

 the pellucid coats of the sheath. No instance of a decidedly 

 immature dart has occurred to me. 



The figures are drawn from specimens obtained near Barton 

 in Hampshire. 



Out of a large series of individuals of this species examined 

 in May, June and July, scarcely 10 per cent, furnished darts. 

 Shells which have lost their brilliancy and assumed a dull, dirty 

 yellow appearance will best reward the dissector. The small 

 number reaching sexual maturity in the months mentioned is in 

 striking contrast to what is observable in most species of land 

 snails. In this respect the present species again resembles its 

 congener Z. nitidus. 



It will now be a matter of interest to ascertain whether those 

 continental forms which the author of British Conchology 

 considers to be varieties of this species are or are not furnished 

 with a dart of this description. I refer to the H. viridula, Menke 

 and the H. vitrina Fer. 



3. Helix virgata Da Costa, pi. iii., figs, n— 17. Dart-sac 



broadly oval, but rather irregular in outHne, united 

 throughout most of its length to the vagina ; occasion- 

 ally obtusely notched at its free-end ; yellowish white. 

 Dart with a stout, curved shaft, increasing gradually 

 from point to base ; furnished with two thin, trans- 

 parent, simple-edged angulated blades ; Length 2 to 

 3 mm. 



The dart of H. virgata is the sole British representative of 

 a peculiar type remarkable for its heavy shaft and angled blades 

 (fig. 13, 14). The angle occurs near the point and from it the 

 edges of the two blades converge rapidly, in nearly straight lines 

 to the point, which they reach. Below the angle referred to, the 

 edges trend gradually downwards in nearly parallel curves, 

 disappearing about half-way down the dart (fig. 15). In less 



