ART. 17 PARASITES OF AMPHIBIA AND EEPTILIA HARWOOD 33 



found, there were five tapeworms in the snake, three of them Ophio- 

 taenias, and two Oochoristicas, belonging to a species that will be 

 described later in this paper. 



MacCallum's (1921) original description of this tapeworm is 

 based on a number of immature specimens, and is therefore quite 

 inadequate. The points of interest mentioned in his paper are: 

 Strobila 1 mm wide, genital pore irregularly alternating, head 0.6 mm 

 wide, suckers 0.2 mm in diameter, a slight eminence (fifth vestigial 

 sucker ?) present. This is admittedly not sufficient for certain iden- 

 tification, but since my material is from the same host species and 

 agrees very closely with the characters given by MacCallum, I re- 

 fer it to his species. A description of the material is given, as it is 

 possible to make out some structures not mentioned by MacCallum, 

 but this description is admittedly somewhat incomplete, because of 

 the mutilated condition of the material. 



Specific diagnosis. — Proteocefhdlus'. A flat white tapeworm. The 

 length can best be estimated by a single piece, with scolex attached, 

 which measured 18 cm. The last segment of this piece was barely 

 mature. Maximum width about 1.3 mm at the level of the first 

 mature segments. The scolex is 0.5 mm wide. It bears a vestigial 

 fifth sucker besides the usual four. The four suckers are about 0.2 

 mm in diameter. The neck is about the same width as the scolex 

 and about 5 cm long. The first segments are much broader than 

 long, and in them the rudiments of the genital organs are already 

 present. They mature very slowly, however, and no mature seg- 

 ments are found until very near the end of the long piece mentioned 

 above. When first mature the segments are somewhat longer than 

 broad, measuring 1.85 by 1.3 mm. They gradually elongate as they 

 mature until they measure 3.85 by 1 mm, when the testes first begin 

 to degenerate. The genital pore lies between the caudal border of 

 the first sixth and the first third of the lateral margin of the seg- 

 ment. It is relatively farther forward in the younger segments. 

 The cirrus is very stout and usually protrudes; the ejaculatory duct 

 is straight. The cirrus sac measures 0.28 to 0.32 mm in length and 

 0.09 to 0.11 mm in width. From the median end of the cirrus sac the 

 coils of the vas deferens reach to the midline. The testes are very 

 numerous and are crowded between the uterus and vitellaria. There 

 are 390 to 420 testes to the segment, and about 60 per cent of these 

 are on the aporal side. The testes vary from 0.09 to 0.32 mm in 

 diameter. The vagina usually opens posterior to the cirrus sac, but 

 segments in which it opens anterior to that structure are not un- 

 common. It lies ventral to the cirrus sac, but it curves dorsad over 

 the vas deferens and lies on the dorsal side of the uterus. The bi- 

 126821—32 3 



