48 



harmonious tints, chiefly of blue grey and ochre, make quite a 

 pleasing picture. 



I have already mentioned the most obvious distinction between 

 the Limaces and the Arions, but I might also call attention to the 

 slime gland at the tail of Arion. This caudal mucus gland, as it is 

 called, is absent in the Liniacidae. Though the members of these 

 two families are all slugs yet the families are widely separated. 



The largest and best known of the Arions is the common black 

 slug, Avion ater. It is a plump animal from four to six inches in 

 length when crawling, and is covered with large elongate tubercles. 

 It IS fortunately common, so one often comes across it, and most 

 country people know it as the " black snail," although it has no 

 shell. It delights in damp fields, hedge-rows, woods, and ascends 

 high up the mountain side. It varies a great deal. On the con- 

 tinent there is a brilliant red slug which some authors consider a 

 form of this species. Though I have seen reddish A. ater in Scot- 

 land they are paler, smaller, and look different to the large red 

 slugs on the continent, but perhaps the hotter summers and autumns 

 abroad may account for the size and brilliancy of these latter. 



The next species. Arum stibfuscus, though much smaller than the 

 black slug, is larger than the three other Arions. It reaches some 

 three inches in length, has been much confused with the last species 

 and is not always easy to separate. It usually has, however, a dark 

 band runnmg across the shield and along the body on each side, 

 and a mixture of yellow in its coloration. It is one of those slugs 

 which may be found on fungus in woods. I took it on one of our 

 fungus forays at Oxshott, but have also taken it in company with 

 Afirioliuiax laeris at the water's edge. There is a curious point 

 about the distribution of this species. It has not, unless quite 

 recently, been taken in the eastern counties. I believe it is not yet 

 recorded for Essex and it would be interesting to find it in Epping 

 Forest, a likely locality. 



One of the commoner garden slugs is Arion hortensis and its 

 sister species Arion circitmscriptim may be found there also. I have 

 sometimes seen them lying side by side under the same stone. 

 They are both rather small, dark on the back, with a small dark 

 band on each side of the shield and along the body. A. horteuHis is 

 slaty-grey with a blackish back and an orange foot-sole. All we 

 have to do with typical specimens is to turn them over and see 

 whether they are yellow or white underneath. They both display 

 themselves well on the saucer but I fancy A. circinnscriptiia is the 

 more lively of the two. The latter species is fond of fungus and 

 may be found at Oxshott as well as in most places, though it has 

 not yet been recorded from Epping where it probably occurs. A. 

 hortensis also occurs in woods but its chief haunts are gardens and 

 cultivated land. 



The last and least of our Arions is A. intennedius, formerly 

 known as A. minimus, a, very small and delicate animal about three- 



