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 sexcoronatum. 

 Head. Enlarged. From Hall, 1919. 



Figure 25.— Mature segment 

 of six-crowned double-pored 

 tapeworm, Dipylidium sex- 

 coronatum. Enlarged. From 

 Hall, 1919, after von Ratz, 

 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 J^lofn/fl. 



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 



Figure 26.— The common double- 

 pored tapeworm. Dipylidium 

 (■'milium. Egg capsule. En- 

 larged. From Stiles, 1903. 



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

 Head, viewed from the front. Enlarged. From Ball, L919. 



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 



