Newton, on the Helices and Limaces. 27 



tapers at both extremities (fig. 2st). Professor Allman 

 {' Rep. Brit. Assoc./ 1846, p. 82) notices that the multifid 

 vesicles, and a peculiar dart, exist in this species, both of 

 these organs relating it to the Helix. In Arion ater the 

 cloaca forms a very definite chamber (fig. 3 c) ; within it is a 

 fleshy body, which partly surrounds the entrance of the 

 oviduct, and is of a subtriangular form, grooved, and crenu- 

 lated at its margins (fig. ^ x). It will be noticed that this 

 body, being placed just within the cloacal chamber, occupies 

 very nearly the position of the multifid vesicles, which are 

 generally situated immediately without it. 



Professor Owen tells us in his " Lectures on the Inverte- 

 brata " that " a short csecal tube is developed from the duct 

 of the spermatheca of H. pomatia, and a very long one from 

 that of H. arbustorum." H. aspersa, H. nemoi'alis, and H. 

 hortensis have also this addition to the spermathecal duct. 

 In the two latter it is, as in H. po77iatia, only a short tube 

 (fig. 8 adst) ; but in the former (fig. 7 adst) it resembles that 

 of H. arbustorum, being considerably longer than the sper- 

 mathecal duct itself. This additional tube enclosed a 

 viscid white substance, Avliich, upon examination with the 

 microscope, was seen to contain spermatozoa. The presence 

 of the spermatozoa here would lead to the inference that this 

 tube is only an additional spermatheca. Swammerdamm 

 thought it to be a duct of communication between the sper- 

 matheca and the oviduct, thus lessening in some measure the 

 distance which the spermatozoa would have to traverse in 

 passing from the former to the latter ; but as it is not found 

 in H. cantiana, H. rufescens, nor H. vir(jata, nor in any of 

 the Limaces referred to in this paper, this idea is very im- 

 probable. It may be mentioned that the spermatheca of 

 H. cantiana (fig. 10 st) is proportionately very large, and of a 

 subtriangular form, though its duct is not so long as in most 

 of the other Helices. 



In H. rufescens there are immediately below the junction 

 of the oviduct with the spermathecal duct four pyriform 

 bodies, two upon each side (fig. 9 d) ; these are in the posi- 

 tion usually occupied by the dart-sac, and there appear, 

 therefore, in this instance, to be four of these organs, but 

 darts were only to be found in the two lower bodies. As it 

 often happens, in other species, that the dart is absent from 

 its sac, it might be thought that it was the case here ; but 

 in all the individuals of this species which were examined 

 darts were never seen in the two upper bodies, while they were 

 invariably present in both the lower ones. 



The dart-sac of H. cantiana, or, more correctly, that 



