112 TRANSACTIONS OF ROYAL SCOTTISH ARBORICULTURAL SOCIETY. 



places in the afternoon, apparently feeding on the bark 

 which probably was softened by the frequent rains. In 

 the grounds of the Laboratory the other shrubs consist of 

 Cotoneaster, jasmine, roses, and fuchsia, but none of these were 

 injured, and it is possible that the bark of the sycamores proved 

 more attractive. Moreover, these attacks may have occurred 

 without being noticed in previous years. 



In looking for information on the subject nothing was found 

 in Leaflet 132 of the Ministry of Agriculture and Fisheries, 

 and Sir David Prain, in his ample experience | at home and 

 abroad, had not met with similar injuries. Sir Sidney Harmer, 

 Director of the Natural History Departments of the British 

 Museum, kindly interested Mr Robson in the matter, and he 

 observes that " Taylor in his monograph treats of the food of 

 H. aspersa pretty fully, but does not mention that it feeds 

 on bark, nor can I find any other records of this. It is 

 very omnivorous, but usually attacks leaves." Prof. Wright 

 Smith, of Edinburgh University, observes "that snails are nicer 

 feeders than slugs, for the latter are capable of anything, 

 even cannibalism. Some species, however, will eat cork." At 

 the instance of Mr Galloway, Secretary of the Royal Scottish 

 Arboricultural Society, Mr J. M. Murray, of the Forestry 

 Commission, kindly communicated with me on the subject. 

 He observes that " Sorauer states that H. aspersa can be very 

 harmful in the garden, devouring the tenderest vegetables, 

 and can even wholly defoliate pear and apricot trees, and of 

 these trees they may also eat the fruit and flowers. I have 

 found snails, I think H. aspersa, on sycamores, poplars, and 

 other trees (even spruce). They destroyed leaves and young 

 succulent shoots of sycamore, and while they certainly weakened 

 the plants, I could not attribute the death of the plants to these 

 attacks. A great deal will depend on the strength of the plants, 

 the number of branches they bear, and the dormant buds that 

 may be present — whether or not the plants are killed. Certainly 

 the damage is worst where there is long, rough grass or weeds. 

 I generally associate the damage with long cocksfoot grass, but 

 this is probably because of the shelter and moist conditions 

 induced by rank clumps of this grass." Mr Murray's experienced 

 remarks are in keeping with the environment at the Marine 

 Laboratory where, during the late quietude, the rank growth of 

 grass and wild plants provided shelter for the snails, while the 



