ASHFORD : ON THE DARTS OF BRITISH HELICID^. 269 



taken as a mucous gland and the shorter one as a repre- 

 sentative of the dart-sac. This is the only species here 

 described which I have been unable to examine, and 

 Schmidt's figure has been reproduced in an adapted form. 



Helix Cartusiana Mull, pi. x., fig. 3. This has a well- 

 developed double group of simple, bifid or trifid mucous 

 glands from 3 to 5 mm. long. Below these and in the place 

 where a dart-sac might be expected is an appendage of very 

 peculiar form, better understood from the figure than by 

 description. Is this organ to be considered a modified 

 dart-sac ? Moquin-Tandon thinks it is, but Schmidt gives 

 reasons for an opposite opinion. The figure is from one of 

 two or three dozen examples favoured by Mr. J. H. A. Jenner, 

 of Lewes, and collected by him in that locality. I found 

 the organ in question very constant in shape, and varying 

 but little in size. 



Helix Cantiana Mont., pi. x., fig. 4. Here we find a new 

 departure. This species has, like the last, two characteristic 

 bundles of mucous glands about 5 mm. long, dividing into 

 3 to 5 blue-white semi-transparent branches. But there is 

 no organ in the usual position of the dart-sac. Lower down 

 we find a long, (10 to 15 mm.) tapering, blue-white 

 appendage joining the common vestibule opposite to, or a 

 trifle lower than, the base of the penis-sheath. Moquin 

 Tandon does not even mention this moit conspicuous 

 organ. Schmidt thinks it cannot be taken as a substitute 

 for a dart-sac on account of its position. He is probably 

 right, for H. pyramidata and H. elegans appear to have 

 mucous glands and dart-sacs in the usual position, and, in 

 addition, lower down, an appendage somewhat similar in 

 character to that in H. Cantiana. An apparently analogous 

 organ in an American species is called by W. G. Binney a 

 ' vaginal prostate.' The figure is from a Christchurch 

 example. 



