ScHARFF — On the Slugs of Ireland. 



539 



examined specimens from Norway and the different parts of Ireland, and find that 

 there is less difference between the East Irish and Norwegian than there is between 

 the West and East Irish. 



The colour of the hermaphrodite gland {h[).), generally of a light brown, 

 varies according to the colom- of the body. The hermaphrodite duct {hd.) is well 

 convoluted. The free oviduct {ov.) opens into a vestibule as in Amaliu, but there 

 is in Arion ater an additional glandular lower vestibule {Iv.) which has by Law- 

 son (18) been incorrectly named cloaca. The upper vestibule {iw) or atrium he 

 distinguishes as the " egg-sac." 



The sperm-duct {sp.) ends in what used to be regarded as a penis, but which 

 Simroth (38) has shown is only the enlarged lower portion of the sperm-duct {sp.) 

 in which the spermatophores or sperm-cases are formed. The receptaculum (rec.) 

 and the " Patronenstrecke " {pat.) of the sperm-duct («/;».) opens into the lower 

 portion of the upper vestibule {uv.). 



Both the oviduct {ov.) and the duct of the receptaculum are provided with 

 powerful retractor muscles {rm.), which in West Coast specimens are attached quite 

 close to the receptaculum and the upper portion of the oviduct, respectively, whilst 

 in East Coast forms these same muscles are almost invariably attached much lower 

 down to the same structures. Of course this alone may not be of much importance, 

 but coupled as it is with dilferences in colour and length of life, the West Coast 

 forms constitute what we may at present regard as a striking variety of A. ater 

 which may become further modified in time. I propose to reinvestigate this form 

 when I have collected more material in the West. 



Reproduction. — The eggs are laid chiefly in August and September, in clusters 

 averaging about fifty in number. I have frequently observed them in fields under 

 heaps of hay and in gardens under stones. They are deposited freely in captivity. 

 They adhere only very slightly to one another, and may be easily distinguished 

 from any of those previously described by their remarkable hardness. They feel 

 quite solid, and owing to their calcareous shells are perfectly opaque. They have 

 a long diameter of 4 mm. and a short one of 3 mm. 



I said above that reproduction takes place chiefly in August and September, 

 but a few specimens, undoubtedly, deposit eggs earlier, for I have seen quite 

 young ones in August, and as the eggs take about 4 to 6 weeks to develop, they 

 must have been deposited in June. 



Throughout the winter large numbers of young ones are to be met with in the 

 garden, and frost does not seem to affect them very much. These young speci- 

 mens (figs. 13 and 14) are invariably of a very light yellow or red — never dark. 

 Generally well-defined black lateral bands run along each side of the body, and are 

 continued on the mantle, ending at its anterior margin ; and all have dark- 

 coloured heads and tentacles. I have no doubt that these young forms, which are 



4 F2 



