THALASSEMA. ANNELIDES. 141 



mouth under the anterior extremity, with a rounded opercu- 

 lum ; the eyes at the extremities of a crescent-formed line. 



C. borealis, Lam. Body elongated, two or three inches long, and 

 the thickness of an earth-worm, with lateral, setaceous, very long 

 cirri ; the posterior segment terminated by an anus. Inhabits 

 northern seas Lam. v. 302. 



Gen 2. THALASSEMA, Lam. Lumbricus, Gmel. 

 Body soft, elongated, subcylindrical, annulose, obtuse posteri- 

 orly, the posterior segments furnished with small spines ; two 

 hooked and golden-coloured spines under the neck ; mouth 

 naked, fleshy, auriform or spoon-shaped, contractile; no eyes, 



T. echiura, Lam. Inhabits the sandy shores of Europe, and dug 

 by fishermen for bait Lam. v. 300. 



Gen. 3. LUMBRICUS, Lin. Lam. 



Body contractile, long, cylindrical, annulose, and the rings fur- 

 nished with very small spines directed backwards ; mouth 

 subterminal, naked, bilabiate, the upper lip largest and pro- 

 jecting ; no eyes ; anus at the posterior extremity. 



The body of these animals is composed of a great number of narrow approxi- 

 mated rings, which appear to be formed of transverse wrinkles by the circular 

 muscles under the skin in contraction. The skin is shining, reddish, and a viscous 

 humour is exuded from it. The Lumbrici live in moist earth, feed on vegetable 

 and animal remains, and come to the surface to couple. They are hermaphrodite. 

 The most common species is known over all the world by the name of the earth- 

 worm. 



L. terrestris, Lin. Body reddish, of a hundred and forty segments ; 

 a prominent annular belt about one-third of its length ; on each 

 side of the belly a row of minute spines to assist in motion. In- 

 habits moist earth in fields and gardens. Penn. Brit. Zool. iv. 

 pi. 20, tig. 2. 



L. armiger, Mull. Body red, the lamellae of the belly lanceolate ; 

 no annular belt. Inhabits Norwegian coasts. Lam. v. 299. 



L. minutus, Lam. Body reddish, with a pale elevated head near 

 the middle ; belly with bifarious spines. Inhabits coasts of Green- 

 land, between stones and the roots of fuci Lam. v. 299. 



FAMILY II HIRUDIXE.E. 

 Body destitute of projecting bristles. 



The animals of this family are generally aquatic, although at Madagascar are 

 found some which are constantly terrestrial, attaching themselves to plants. 



Gen. 4. ERPOBDELLA. Hirudo, Gmel. 



Body flattened, terminated posteriorly by a prehensile disc ; 

 mouth destitute of teeth or jaws ; ocular points. 



The animals of this genus were named Helluo by M. Ocken, and the present ge- 

 neric term was substituted for this by Blainville. M. Lamarck doubts very much 

 whether they belong to this division. 



E. vulgaris, Lam. (H. octoculata, Lin.) Body elongated, fuscous 



