ART. 17 PAEASITES OF AMPHIBIA AND EEPTILIA HARWOOD 39 



both species in having much smaller suckers. There are also differ- 

 ences in the size of the cirrus sac and the position of the genital 



organs. 



OOCHORISTICA ELAPHIS. new species 

 Plate 3, Figure 6 



SpecifiG diagnosis. — Oochoristica: A slender, white, semitranslucent 

 tapeworm. Length 65 to 75 mm. The scolex is about 0.35 mm wide 

 and bears four circular suckers about 0.145 mm in diameter. The 

 neck is not sharply marked off from the scolex. It seems to be 5 or 

 6 mm long. The mature segments are nearly square, about 0.75 mm 

 each way. The genital pore is slightly posterior to the end of the 

 first fourth of the lateral margin. The cirrus sac is 0.145 mm long 

 by 0.068 mm wide. The vas deferens is a much convoluted structure 

 extending mesad to the ovary where it vanishes. The testes are very 

 variable. The extreme counts are 30 to 53. They overlap one an- 

 other and the shell gland, so that counting is more difficult than 

 usual. The ovary is a bilobed structure lying near the center of the 

 segment. It is about 0.3 mm broad. Behind it lie the shell gland and 

 vitellaria. The vitellaria are more extensive than usual. Not only 

 do they underlie the testes but they extend laterad as far as or farther 

 than the ovary. The vagina starts from a seminal receptacle dorsal 

 to the shell gland, and runs first cephalad, then curves laterad 

 around the lobe of the ovary, and finally opens into the genital 

 atrium just posterior to the cirrus sac. Both genital ducts pass be- 

 tween the lateral tubes of the excretory system. The ripe segments 

 are about one and one-half times as long as broad, and are crowded 

 throughout with eggs. The eggs measure about 50/t in diameter and 

 the embryos about 34/i. 



Host. — Elaphe ohsoleta Undheimerii. 



Habitat. — Intestine. 



Locality. — Houston, Tex. (Houston Zoological Gardens). 



Type specimen.— \] .'^:^M. Helm. Coll. No. 31676. 



Remarks. — The snake from which the type material was taken died 

 in the Houston Zoo. Presumably it was captured somewhere in 

 the vicinity of Houston, but the exact locality is unknown. It had 

 refused to eat during several weeks of captivity, and this fact may 

 have affected the taf>e worms somewhat. The worm most closely 

 resembles Oochoristica americana described above. Like this form 

 the testes are distributed in more than one layer, but in 0. elaphis 

 the vitellaria are much more extensive and underlie the testes. Fur- 

 thermore, O. elaphis seems to be a much smaller and more delicate 

 form. 



