NO. 1780. 



A NEW CESTODE PARASITE— HALL. 



145 



j^ht. 



white mice, and one field mouse, Microtus pennsylvanicus, these 

 being animals closely related to those which would probably form 

 part of the food of the dog and lynx from which the tapeworms 

 were obtained. The rabbit was 

 especially indicated as a pos- 

 sible host in that the remains 

 of a rabbit were found in the 

 cage with the lynx when it ar- 

 rived in Washington, and the 

 infection in the case of the lynx 

 was evidently of very recent 

 occurrence. The rabbits were 

 killed and examined at inter- 

 vals of from one week to three 

 months eighteen days after 

 feeding, the white mice after an 

 interval of one month, and the 

 field mouse after an interval of 

 two months thirteen days. Care 

 was taken to use proglottids 

 that had been kept moist for 

 some time as well as fresh ones 

 and it seems fairly certain that 

 the eggs were capable of infect- 

 ing the premier intermediate 

 host. Nevertheless, no signs of 

 infection were found in any of 

 the experiment animals. Dur- 

 ing a visit to Fallon, Nevada, 

 the "WTiter was struck b}" the 

 abundance of rodent burrows 

 in that locality, and it seems 

 not unlikely that the interme- 

 diate hosts of the tapeworm 

 belong to one or several of the 

 numerous species of rodents 

 around Fallon. 



The salient characteristics of 

 Tsenia halaniceps are as follows: 

 A prominent rostellum with the 

 hooks set well forward of the 

 suckers; large hooks which display a tendency to fall ofl' readily; a 

 uterus which forms so many lateral branches which become approxi- 

 mated or fused that the uterus becomes practically a lobed pouch, 



Proc.N.M.vol.39— 10 12 





ec 



J^ost. 



4omm. 

 Fig. 9.— Sagittal section showing cross section 

 of transverse canal between adjacent pro- 

 GLOTTIDS. c, CiERus; c. p.. Cirrus pouch; /. e. c, 

 Longitudinal excretory canal; I. m., Longi- 

 tudinal muscles; n, Nerve; t. e. c. Transverse 

 excretory canal; t. m.. Transverse muscles; 

 nt., Uterus; v, Valve; va., Vagina. 



