344 



THE ANIMAL PARASITES OF MAN 



Of this species only two specimens have been recorded ; they 

 occurred in human beings and were sent at different times to the 



FIG. 248. Tania confusa : mature 

 segment showing central uterine stem, 

 bilobed ovary, globular shell gland, trian- 

 gular vitellarium, scattered testes, cirrus, 

 vas deferens, and vagina. 15/1. (After 

 Guyer.) 



FlG. 249. Tcenia con- 

 fusa : gravid segment. 

 25/1. (After Ward.) 



first describer of them by a doctor in Lincoln (Nebr.). Perhaps 

 Tcenia solitim, var. abietina, Weinld., which was found in a Chipe- 

 way Indian, is of the same species in spite of the shorter segments. 



Taenia echinococcus, v. Sieb., 1853. 



Syn. : Tcenia nana, v. Ben., 1861 (nee v. Sieb., 1853) ; Echinococcifer 

 echinococcus, Weinld., 1861. 



Tcenia echinococcus measures 2*5 to 5 or 6 mm. in length ; the head 

 is 0*3 mm. in breadth, and has a double row of twenty-eight to fifty 

 hooklets (on an average thirty-six to thirty-eight) on the rostelltim. 



The size and form of these hooklets vary (the larger ones are 

 0*040 to 0*045 mm - m length, the smaller ones are 0*030 to 

 0*038 mm. in length). The suckers measure 0*13 mm. in diameter; 

 the neck is short ; there are only three or four segments, the posterior 

 segment being about 2 mm. in length and 0*5 mm. in breadth. The 

 genital pores alternate ; there are forty to fifty testicles ; the vas deferens 



