CHAPTER XIX 

 BRANCH VERMES:* THE WORMS 



THE EARTHWORM (Lumbricus sp.). 



TECHNICAL NOTE. Obtain live earthworms of large size, killing 

 some in 30^ alcohol and hardening and preserving them in 8o# alco- 

 hol, and bringing others alive to the laboratory. The worms may 

 be found during the daytime by digging, or at night by searching 

 with a lantern. They often come above ground in the daytime 

 after a heavy rain. Live specimens may be kept in the laboratory 

 in flower-pots filled with soil. " They may be fed on bits of raw 

 meat, preferably fat, bits of onion, celery, cabbage, etc., thrown on 

 the soil." 



External structure (fig. 25). Examine the external 

 structure of live and dead specimens. Which is the ventral 

 and which the dorsal surface ? Which the anterior and 

 which the posterior end ? Note the segmented condition 

 of the body; the number of segments or somites, and their 

 relative size and shape. Note absence of appendages such 

 as limbs and the presence of locomotor seta (short bristles). 

 How many setae are there on each segment and what is 

 their disposition ? The moutJi is covered by a dorsal 

 projection called the prostomium. The anal opening is 

 situated in the posterior segment of the body. The broad 

 thickened ring or girdle including several segments near 



* The author recognizes the untenability of the group Vermes as a group 

 co-ordinate with the other branches of the animal kingdom, and that 

 "Vermes" has been discarded in modern text-books. But because of the 

 very scant consideration whic^i can he given the various kinds of worm like 

 animals the course of the older text-books will be followed, and all of the 

 worm-like animals, as far as referred to in ihis book, be considered under 

 the group name Vermes. 



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