ii6 



OBSERVATIONS ON THE PAIRING OF ARION ATER (L). 



By LIONEL E. ADAMS, B.A. 



(Read before the Society, March gth, 1910). 



Very little seems to be known of the breeding habits of our slugs i; 

 we may judge by the lack of information contained in the text books. 

 In Ferussac's work ^ there are figures of the pairing of Limax vmxi- 

 f/ius L. and Arum ater (L.), but all these are evidently drawn from 

 memory and are wrong in detail; the descriptions, too, are vague and 

 incomplete; these, however, are all that the student has to rely on, and 

 even accurate figures of mere anatomical detail are quite inadequate to 

 give an idea of the exact method of employment of the organs figured. 

 I am glad, therefore, to have had the opportunity lately of an obser- 

 vation which may help to supply the deficiency. 



\\\ mid August, 1896, while searching for shells with Mr. C. E. 

 Wright, of Kettering, one afternoon at Shepherdswell, near Dover, I 

 noticed a couple of A. ater pairing in an open field among the short 

 grass, but supposing at the time that the act must be common enough 

 to be well known I made no notes. Subsequently I learnt that how- 

 ever common it may be, it does not seem to have been observed by 

 British conchologists. Although I and many others have been on the 

 look-out for the chance of an observation ever since, it was not until 

 Sept. I, 1909, that an opportunity presented itself while I was staying at 

 Beeding in Sussex, and curiously enough Mr. C. Oldham wrote a few 

 days afterwards to tell me that he had also witnessed a similar occurr- 

 ence at Oxhey Woods near Watford on the afternoon of Sept. 4th, 1909. 



Is it mere coincidence that the only three occurrences that have 

 been noticed by myself and many others, who have been on the look- 

 out for thirteen years, and who spend much time in the country, should 

 be all late in August or early in September, or can it be that the 

 "season" of this species is restricted to a very short period of the year? 

 I used to think that the pairing took place at night, but extensive 

 lantern search always failed to discover it in the lanes round Stafford 

 where the species was exceedingly abundant. I used to notice that 

 hundreds would be found abroad about dusk, but very few late at 

 night, and this was the case on the occasion about to be described. 

 The habits of this species are generally diurnal or crepuscular, not 

 nocturnal. 



On September i, 1909, after a spell of nine days' dry weather, 

 rain commenced steadily at 3 p.m., and the thirsty moUusks came 



I " Histoire Naturdle, g^n^rale et particuliere, des Molkisques Terrestres et Fluviatiles" 

 (1819). 



