60 HELMINTHOLOGY 



b. The head, or scolex, is at the tapering end of the worm, and 

 is more or less globular. 



c. Back of the head are the gradually broadening segments, 

 or proglottides. The oldest proglottides are the farthest removed 

 from the head, and these drop off most readily. 



B. Under a compound microscope examine stained and 

 mounted specimens of heads and proglottides from T&nia sagi- 

 nata, the beef tapeworm of man, and Dibothriocephalus latus, 

 the fish tapeworm (closely related species will serve just as well). 



a. Head of Tcenia saginata. Notice the four cup-shaped 

 suckers, and a projecting rostellum, on which there are no hooks. 



b. Head of Bothriocephalus latus. Notice the presence of 

 two groove- or slit-like suckers; the rostellum is absent. 



c. A stained proglottid (not too mature) of Tcenia saginata 

 should show, i, the uterus as a median-branched tube, tree-like 

 in form, which extends nearly the entire length of the proglottis, 

 2, the ovaries, bilobed, finely branched bodies situated in the 

 posterior end of the proglottis, uniting medianally with, 3, the 

 vitellogene gland, situated along the median posterior border; 

 4, the vagina, a straight tube extending from the median pos- 

 terior field to 5, the genital pore, on the median lateral border; 

 6, the testes, consisting of a large number of bodies distributed 

 throughout the field as fine dots, and joined by 7, the vas efferent, 

 which again connects with 8, the vas deferens, a coiled tube 

 paralleling the vagina and also connecting with the genital pore, 

 through 9, the cirrus pouch; 10, the excretory system may be seen 

 as two transparent collecting tubes on either lateral border (four 

 longitudinal tubes and a transverse connecting tube along the 

 posterior border). 



C. Compare with the above a stained proglottid of Both- 

 riocephalus latus, the fish tapeworm already mentioned in B, as 

 to form and position of the uterus and the position of the genital 

 pore. 



Draw a head and a proglottis of each species, labelling all the 

 parts found. 



