SENSE ORGANS BODY-CAVITY 



355 



iv / 



But worms are epicures, and exhibit a decided taste and preference 

 for certain articles of diet. Like their fellow tiller of the soil, 

 the agricultural labourer, worms have a keen relish for onions, 

 which, however, they must recognise by 

 the smell. They prefer green cabbage 

 to red, celery to both, and raw meat 

 appears to be the greatest delicacy that 

 can be offered to them. It is only sub- 

 stances they are not likely to meet 

 with, such as perfumes, tobacco, and 

 paraffin, that produce no impression 

 upon the worm's sense of smell. 



Coelom and Vascular System. 

 When an earthworm is dissected the 

 various organs are seen to lie in a 

 fairly spacious cavity, which is inter- 

 rupted and divided into a series of 

 chambers by the mesenteries or septa 

 which stretch across from wall to wall 

 of the body, and correspond roughly in 

 their position to the grooves which 

 separate the body externally. This 

 cavity, common to all the higher 

 animals, is known as the coelom ; it is 

 lined by cells, which cover the intes- 

 tines as well as the inside of the body- 

 wall ; and upon the intestine assume the 

 form 





so characteristic of the group, 

 namely, that of large yellow cells loaded 



with secreted matters, and called " chlora- FIG. 190. Sparganophilus tame- 

 gogen-cells " by Claparede. The coelom 

 communicates with the exterior by 

 means of the dorsal pores, the nephridia, 

 and the ducts of the reproductive organs. 

 As in all animals which possess a coelom, 

 the reproductive tissues, ova and sperm, 

 are developed on its walls. 



The vascular system of the Oligochaeta forms a system of 

 perfectly closed vessels, which ramify into fine capillary networks 

 in the body-wall, in the coats of the alimentary canal, and upon 



sis; general anatomy, x 3. 

 (After Benham.) I-XVIII, 

 segments. 1, 4, 6, Perivis- 

 ceral vessels (6 is one of the 

 hearts) ; 2, 3, 7, dorsal vessel ; 

 5, spermatheca ; 8, sperm 

 sacs ; 9, intestino-tegument- 

 ary vessels ; 10, ovary ; 11, 

 12, integumentary vessels. 



