AET. 17 PARASITES OF AMPHIBIA AND EEPTILIA HAEWOOD 41 



The ripe segments are four to six times as long as broad, and the 

 eggs are scattered sparsely throughout. The eggs are 55/t in diameter, 

 and the embryos are 30/a in diameter. The excretory system is very 

 unusual. Plate 4, Figure 1, is a diagrammatic reconstruction of a 

 terminal segment of a young worm studied in sections. At the 

 caudal end of the terminal sterile segment there are the usual median 

 bladder and pore. Four excretory tubes of approximately equal size, 

 one pair dorsal to the other, leave the bladder but very quickly come 

 together to form a single pair of tubes. These again split apart and 

 come together again, a process that is repeated several times. By the 

 time the end of the terminal fourth of the segment is reached, how- 

 ever, the dorsoventral splitting ceases, and the tubes are single on 

 each side throughout the rest of the segment. At irregular intervals 

 throughout the worm, however, the tubes split again into dorsal and 

 ventral parts for short distances, and in one instance such a split 

 forms a loop through which the reproductive ducts pass. There are 

 also some branch tubes that form anastomoses in the median portion 

 of the worm, but these are rather infrequent. A scolex with about 

 3 mm of neck was sectioned, and throughout this area the usual 

 dorsal and ventral excretory ducts were present. It is evident, there- 

 fore, that the single pair of tubes existing throughout the greater 

 part of the worms represents a fusion of dorsal and ventral vessels, 

 this fusion being not quite complete. 



Host. — Phrynosoma cornutwin. 



Habitat. — Intestine, 



Locality records. — Houston and Anderson, Tex. 



Tyj)e ^^<^c^/?^€w.— U.S.N.M. Helm. Coll. No. 31677. 



Family NEMATOTAENHDAE Luhe, 1910 



Genus CYLINDROTAENIA Jewel, 1916 



This genus was proposed by Jewel for a single species, taken from 

 the intestine of various North American amphibians. More recently 

 Joyeux (1924) has reported it from South Africa. 



CYLINDROTAENIA AMERICANA Jewel, 1916 



Specimens taken from Acins gryllus., Hyla squlrella., Pseudacris 

 triseriata.f and Leiolopisma laterale are referred to this species. It 

 is perhaps a little surprising to find an amphibian cestode in a rep- 

 tile, but in every detail of the anatomy the worms from Leiolopisvia 

 laterale matched Jewel's description, and the measurements fell 

 within the variations which she recorded. 



It is interesting to recall Joyeux's (1924) comparison between his 

 material from African amphibians and Jewel's description. The dis- 



