Field Notes. iii 



MOLL use A. 



Early Mollusca at Middlesbrough. — My experience has 

 been that slugs in anything like mild weather are as much 

 astir and more destructive, if anything, to plant life in the 

 early part of the year than at any other period. Noticing 

 about Christmas time that some of my rare plants and early 

 flowering Crocus species showed signs of their ravages, I had 

 a hunt with a lamp on the evening of January ist, and by 

 looking over certain plants, found and killed 150 in a very 

 short time, and over a very limited area, mostly Agriolimax 

 agresHs and Avion Iiortensis, with a small number of the larger 

 Amalia marginafa ; on two other nights within about one 

 week I got 130 and 100 respectively. This pest has been worse 

 this autumn and winter than usual, probably owing to the 

 very favourable conditions for breeding during the past year. 

 Autumn and winter flowering Crocus species have suffered 

 especially badly, having the flower buds eaten into or very 

 often eaten through at the lower part of the flower stem. — 

 T. AsHTON LoFTHOUSE, Linthorpe, Middlesbrough. 



The slugs mentioned by Mr. Lofthouse are the most 

 destructive of our British species, but their ravages during 

 the milder intervals in winter are more noticeable because of 

 the scarcity of young and succulent growths at this period. 

 Early spring, when all plant life is bursting into vigorous 

 growth, is the season of the slug's greatest voracity, as all their 

 vital functions are then in full activity, and all gardeners 

 can testify to the myriads of seedlings they destroy at this 

 time. Though many garden plants have had their ranker 

 qualities more or less eliminated by selective cultivation, 

 yet all plants are more or less efficiently protected from snails 

 and other enemies by a wonderful variety of chemical and 

 mechanical contrivances, so that it is likely that the ravages 

 of these pests would become much more serious if the pro- 

 tective devices of the plant world could be more readily 

 overcome. — Jno. W. Taylor, February 12th, IQ21. 



MAMMALS. 



Reported Occurrence of a Marten in the Levisham 

 Valley. — Hearing that a Marten had been seen in the North 

 Riding, I wrote to Mr. J. D. Tomlinson, who kindly replied 

 as follows : — ' The localit}' is Levisham Valley, about 7 

 miles north-east of Pickering. About noon on the 13th 

 October I was walking through a hill-side plantation about 

 300 yards from my house. The wood is generally quiet and 

 is strictly preserved, and faces east. There is much natural 

 cover. The trees are mostly Douglas Fir, Larch, Oak, 

 Ash and Lime. There is a good flow of water from a spring 



1920 Mar. 1 



