MALACOZOA. GASTEROPODA. PULMOBRANCHIATA. 79 



I first met with it in my garden, in May, 1 842, while search- 

 ing for specimens of Limax agrestis, and was at once struck hy 

 its very elongated form. Even when contracted, it is nearly 

 as slender as Limax agrestis when extended. Its slime is 

 colourless and transparent ; but leaves a shining whitish, opa- 

 lescent trace, and it exudes, when irritated, an opaline greenish- 

 blue mucus. At night, or by day in gloomy weather, it very 

 frequently ascends trees, to a great height. From the middle 

 of June it disappears ; but I have found it again in October 

 and November. 



Common in many places about Old Aberdeen. 



Limax marginatus. Mull. Verm. Terrestr. et Aquat. ii. 10. 



Limax marginatus of Draparnaud appears to be different. 



FAMILY II. HELICINA. 



Animal with the body elongated, united anteriorly 

 with the foot, spirally rolled, and covered with a shell ; 

 the head and tentacula retractile into the skin, which 

 covers them as a sheath ; four tentacula ; the eyes situated 

 at the tip of the upper pair ; orifice of the pulmonary 

 cavity on the right side of the neck ; the mantle forming 

 a collar; the orifice of the generative organs near the outer 

 base of the right upper tentaculum ; the foot very large. 



Shell spiral, orbicular and depressed, globose, ovate, 

 or cylindrical ; with the mouth roundish, ovate, or semi- 

 lunar, its margin thickened ; the axis perforated in young 

 shells, but the umbilicus often concealed by the reflec- 

 tion of the inner lip in old individuals. 



The species are herbivorous, feeding on the tender 

 parts of plants. They come abroad chiefly in the morn- 

 ing and evening, or after rain ; remain concealed in 

 obscure places during the heat of the day; in long 

 droughts close the mouth of the shell with a membrane 

 secreted by the part of the mantle which encloses the 

 foot ; in winter, having retired into a hole or crevice, or 

 among moss, close the mouth of the shell in the same 

 manner, and remain torpid until the return of heat. 



GENUS 1. HELIX SNAIL. 

 Animal elongated ; the body spiral ; the mantle forming 



