SLUGS. 301 



have living offspring ; others are produced from eggs, and, 

 what is worthy of remark, each egg contains many 

 young ones. Several of the smaller kinds may be 

 multiplied by cutting them in two, each part afterwards 

 becoming a perfect animal. The species best known is 

 the Medicinal Leech, which is employed by surgeons, for 

 the extracting of blood from the human body. It is of 

 an olive-black colour, with six yellowish lines on its 

 upper part, and spotted beneath. 



ORDER II. MOLLUSCOUS WORMS. 



These animals have their name from the soft and gela- 

 tinous nature of their bodies. The greater part of them 

 are inhabitants of the ocean; but several reside in fresh 

 waters, and others on the land. Some of them, as the 

 cuttle-fish and medusa, have the power of moving from 

 place to place, by swimming ; others, like the slugs and 

 aplysia, by crawling; and others, like the amphitrites 

 and sea-anemones, are fixed to one spot. They vary 

 considerably in form ; but most of them have arms, or 

 tentacula, as they are usually called, which serve them 

 either for motion, or for the bringing of food to their 

 mouth. The principal tribes are the Slugs, Sea-anemones, t 

 Cuttle-fish, and Star-fish. 



The SLUGS are all land animals ; and several of the 

 species are too well known, by the depredations which 

 they commit in gardens and other cultivated ground. 

 Some of them, however, are able to subsist for weeks, 

 and even for months, without food ; and if their head or 



