28 



CIRCULAR 338, U. S. DEPT. OF AGRICULTURE 



Probably the most common of the tapeworms in the dog is the 

 common double-pored dog tapeworm, Dipylidium caninum. This 



/fomrrt 



Figure 24.— The six-crowned double-pored 

 tapeworm, Dipylidium aexcorormtum. 

 Head. Enlarged. From Hall, 1919. 



FiGuaE 25. — Mature segment 

 of six-crowned double-pored 

 tapeworm, Dipylidium sex- 

 coronatum. Enlarged. From 

 Hall, 1919, after vpn Rte, 

 1900. 



tapeworm and a closely related species, the six-crowned double-pored 

 tapeworm, D. sexcoronatum, have more than two circlets of hooks on the 

 head (fig. 24), and have 

 a genital pore on each jAoTTiJn. 



side of each segment 

 (fig. 25); the thin-shelled 

 eggs occur in egg cap- 

 sules (fig. 26) and are 

 often found in these 

 capsules in the feces. 

 The segments may be 



FisuBE 26.— The common double- 

 pored tapeworm, Dipylidiwm 

 caninum. Egg capsule. En- 

 larged. From Stiles, 1903. 



Figure 27.— The serrate dog tapeworm. Taenia pisiformis. 

 Head, viewed from the front. Enlarged. From Hall, 1919. 



white or pink, and the terminal segments break off from time to time 

 and either escape in the feces or creep out of the anus; such escaping 



