MILAX SOWERBII. 155 



destructive _ to bulbs and tubers and also to flowering plants of many 

 kinds; it will devour fresh or decaying fungi, partially decayed cabbages 

 and other vegetables or fruit, and even carrion does not come amiss. 



Its diet is, however, not restricted to such pabulum, as it is also actively 

 predatory, and will attack and devour live worms, slugs, and even smaller 

 or weaker individuals of its own kind, though amply provided with suit- 

 able vegetable food. In captivity Mr. Gain offered it 196 varieties of 

 food, 152 of which were more or less nibbled, while 74, however, were quite 

 readily taken, though only potato, carrot, and Boletus edulis were eagerly 

 devoured. 



The animal is of quite inactive habits, crawling slowly, often resting, 

 and when doing so, or when touched or disturbed, withdrawing its head 

 beneath the mantle and shrinking to about half its length, contracting 

 itself almost into a semicircle; when thus contracted the keel becomes 

 sinuous and parts of the body appear indented as though injured at those 

 points. 



Its tenacious mucus enables it, especially when young, to readily form 

 mucus threads for the purpose of descending to the ground or to a lower 

 level, although during the operation the ordinary crawling position of the 

 body is not maintained, but becomes so much twisted that the dorsal and 

 ventral surfaces of the body may be presented to view together. 



The body slime may also at times cause the adherence of particles of 

 earth to the skin, and the animal then closely resembles a lump of earth, 

 assimilating thus to the ground upon which it rests. 



Fossil. — M. sowerbii is cited by Jeffreys as an Upper Tertiary fossil, 

 but the record was probably based on an erroneous identification ; it has, 

 however, been definitely reported from the Holocene deposits at Maid- 

 stone, East Kent, by Kennard & Woodward, and found by Mr. A. S. 

 Kennard at the base of a rainwash deposit associated with bone fragments 

 and Roman pottery, on the site of Roman buildings at Darenth in 

 West Kent. 



Parasites. — Like 31. gagates, it is very liable to be infested with an 

 Acarus, probably the PMlodromus limacum, these in some cases being so 

 numerous as probably to cause some inconvenience to their host. 



Variation. — Milax sowerbii has been observed to vary in its external 

 colouration from pure white, through yellow, grey, or brown, to an almost 

 uniformly black colour. 



Generally speaking, this species is not a very variable one, and the 

 modifications that take place seem to be mainly due in the darker varieties 

 to the increase or diffusion of the black pigment, and in the paler forms to 

 its more or less complete suppression. 



This pigmentation may also be more or less restricted in the area 

 occupied, and become correspondingly intensified, as in the var. bicolor, in 

 which the coloration becomes greatly enriched. 



The Sicilian variety oretea is remarkable for the development of a 

 longitudinal median zone of black pigment on the shield, a feature not 

 previously remarked in the species. 



The M. marginatus var. fulva of Paulucci is, according to Lessona & 

 Pollonera, merely a juvenile form of M. carinata. 



VARIATIONS IN COLOUR AND MARKINGS OF ANIMAL. 



Var. alba Taylor. 



Animal entirely white. 

 Pembroke — Tenby, A. G. Stubbs. 



