Occasional Papers of the Museum of Zoology 7 



tail, (3 ) rarely in the muscles of the tail. A careful examina- 

 tion has failed to reveal their presence in the connective tissues 

 or lymph spaces about the oral cavity, or in the muscles or 

 connective tissues of the body anterior to the tail except as 

 above noted. 



Some attempt was made to determine the relative numbers 

 of the parasite in the various parts of a heavily infested snake. 

 In the serosa about the extreme upper oesophagus they were 

 not numerous while in the thickened mesenteries of the an- 

 terior part of the body they were present in considerable num- 

 bers. From this point to the posterior limit of the body cavity 

 the parasites occurred very numerously, the greatest number 

 occurring in the posterior third of the body. In the fat bodies 

 they were abundant. A small piece of mesentery taken from 

 this region and mounted on a slide contained after mounting 

 more than 300 cercaria while more than 60 were shaken free 

 in the course of manipulations incident to mounting. A small 

 group of cercaria as they occur under the mesentery is shown 

 in Fig. 2. A rough but very conservative estimate of the num- 

 ber of parasites in the mesentery, fat-bodies and peritoneum is 

 about 500,000 to 700.000. In the muscles and lymph spaces 

 immediately back of the anus there were but few cercaria but 

 a little farther back they occtirred in enormous numbers. In 

 arriving at an estimate of the number of parasites in the tail 

 region the following points were taken into consideration : the 

 nimiber of parasites in a single section of the tail, the length of 

 the tail, the swollen condition of the tail, and the extremely 

 large number of cercaria shaken out from the loosened scutes 

 and found in the bottom of the container. Judging from these 

 criteria there must have been at least 250.000 to 350,000 para- 

 sites in the tail region, a grand total for this snake of 750,000 

 to 1,050,000 parasites. 



