APPENDIX 565 



Fresh Tapeworms are rarely obtainable. Laboratory specimens are 

 preserved in formalin. 

 The Tapeworm. 2. Note : head, neck, proglottides (Fig. 129, 5). 



3. In head, under magnification, note : suckers, 

 hooks (Fig. 129, 4). 

 40. In young proglottides, stained and mounted, note : excretory 

 canals ; testes and vas deferens ; ovary, uterus, vagina 

 (Fig. 130). 

 b. In old proglottis, note : large, branched uterus, with thick- 

 shelled fertilised eggs (Fig. 129, 6). 



10. In transverse section of a proglottis, note : cuticle, nuclei of 



ectoderm withdrawn into deeper parts of cells lying in 

 superficial region of parenchyma ; longitudinal muscle fibres ; 

 layer of circular muscle ; excretory canals ; nerve cords ; 

 testes, with developing spermatozoa ; uterus, with fertilised 

 e gg s ! yolk glands (Fig. 131). 



11. In cysticercus, note : head with hooks and suckers, young 



proglottides ; bladder (Fig. 129, 3). 

 Fresh cysticerci of a tapeworm which infects the dog may often be 

 found in the mesentery of the rabbit. On being placed in warm salt 

 solution, some of them will evert the head. 



If the Earthworm be studied during the winter, advantage should be 

 taken beforehand of good weather for obtaining speci- 

 The Earth- mens. They can be kept alive in damp leaves and earth 

 worm. for some weeks. 



1. The movements and habits of earthworms are 

 best studied in the field. Darwin's Earthworms and Vege- 

 table Mould is an interesting work on this subject. 



2. Note : in dorsal view, prostomium, peristomium, following 



segments, clitellum, anus (terminal) ; in ventral view, mouth, 

 setae, genital pores (Fig. 134). 



3. Extract a seta with forceps and examine it under low power 



(Fig. 135)- 



4. Pin the worm ventral side downwards and stretch it well. 



Open it by a cut along the dorsal middle line from the 

 prostomium to segment 25, turn the body-wall outwards, 

 snipping through the septa, and pin. Note : septa ; 

 nephridia ; suprapharyngeal ganglia ; mouth, pharynx, 

 oesophagus, crop, gizzard, intestine ; vesiculse seminales ; 

 spermathecse (these mark segments 9 and 10, and thus 

 enable the other segments to be identified) ; dorsal blood 

 vessel, hearts, contraction of these if the worms have been 

 recently chloroformed (Figs. 138, 405, diagram). 

 50. Cut through the gut just behind the gizzard, lift it with 

 forceps, and working forwards separate it from the septa. 

 In segment 13 note the ovaries before cutting the septum 

 in' front. Be careful not to remove the vesiculse seminales. 

 Cut through the pharynx behind the suprapharyngeal 

 ganglia and remove the alimentary canal. Note the 

 parts mentioned above, and also oesophageal glands and 

 pouches. 



