Seasonal Notes 



581 



There are many species; they may be arranged in three 

 divisions : — 



(1) The shell-slugs {Testacellida). Carnivorous and sub- 

 terranean forms remarkable in having an external shell 

 situated on the tip of the tail. They are aliens, and rarely 

 met with except in large nursery gardens. They prey upon 

 earthworms and small slugs, and are therefore gardeners' 

 friends. 



(2) The true-slugs (Limacida). Shell concealed beneath 

 the mantle, the breathing orifice situated on its anterior part. 

 This division includes (with many others) the well-known 

 Limax maximus, the largest British species. It is a grey slug, 

 usually spotted with black on the mantle, and having black 

 lines on the body. It may be found around pumps and in 

 other damp situations. 



It is infested with a minute parasitic mite (Philodromus) 

 which can be detected with the unaided eye as it runs in and 

 out of the breathing orifice. 



(3) The snail-slugs (Avionidce). These differ from the true 

 slugs in having the breathing orifice situated towards the 

 front of the mantle, or nearer to the tentacles. 



The common black slug of the hedges and fields (Avion atev) 

 is a well-known representative of the group. It is also in- 

 fested with the mite alluded to. This slug is subject to great 

 variation in colour, being sometimes red, brown, and even 

 yellow or white. The members of this division are well- 

 known garden pests, the greatest offender being the little 

 white or speckled field slug, Agviolimax agrestis (see p. 218). 



Birds that nest in April and May are : The Ring Ouzel, 

 chiefly in the West and Midlands in moorland and moun- 

 tainous localities. It much resembles the Blackbird in habit, 

 but may be at once distinguished by the white throat-band. 

 It visits Hindhead and Haslemere for short stays in Spring 

 and Autumn, probably on its way to and from Dartmoor (see 

 White's "Selborne"). The Stonechat nests at the base of 

 a furze-bush on commons. The Dartford Warbler or Furze 



46 



