552 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. 57. 



ovarian and testicular zones. Uterus disposed in a few loops in the 

 median field, none in front of the genital pore. 



Type species. — Apophallus rrmehlingi (Jagerskiold, 1899) Liihe, 

 1909. 



KEY TO SPECIES. 



Vitellaria extend a short distance anteriorly beyond the 

 level of the ventral sucker and encroach upon the 

 median field in this neighborhood ; eggs 36 to 40 n long ; 

 American Apophallus brevis. 



Vitellaria do not extend anteriorly beyond the level of the 

 ventral sucker and do not encroach upon the median 

 field in this neighborhood; eggs 32.4 fi long; Euro- 

 pean Apophallus mnehlingi. 



APOPHALLUS MUEHLINGI (JagerskioW, 1899) Luhe, 1909. 

 Fig. 20. 



1898. Distomum lingua Ceeplin of Muehling, 1898a, pp. 21-22; 18986, 



pp. 29, 94t-96, pi. 3, fig. 16 (in Lanis ridibundus; misdetermina- 

 tion). 



1899. Distomum muehlingi Jagerskiold, 1899a, p. 7 {lingua of Muehling 



renamed as new species). 

 1899. Tocotrema muehlingi (Jagerskiold, 1899) Looss, 1899?), p. 585. 

 1909. Apophallus muehlingi (Jagerskiold, 1899) Lxjhe, 1909, p. 62, fig. 53 



(type of Apophallus) . 



Speci-flc diagnosis. — Apophallus: Length, 1.2 to 1.6 mm.; width, 

 0.19 to 0.23 mm. Body much elongated, constricted near the middle 

 in the region of the ventral sucker. Cutaneous scales, 2.9 [i long. 

 Oral sucker, 54 [x in diameter. Prepharynx well developed (about as 

 long as the diameter of the oral sucker according to Muehling's illus- 

 tration). Pharynx, 37 [x in diameter. Testes globular, near the pos- 

 terior end of the body ; right testis obliquely behind the left. Ventral 

 sucker of about the same size as the oral sucker. Genital sinus 

 median, immediately in front of the ventral sucker. Seminal vesicle 

 well developed, S-shaped, in median line behind the ventral sucker. 

 Ovary globular or piriform, on right side of body between testes and 

 ventral sucker, but nearer to the anterior testis than to the ventral 

 sucker. Vitellaria do not extend anteriorly beyond the level of the 

 ventral sucker and do not encroach upon the median field in this 

 neighborhood. Posteriorly they are numerous in the median field 

 behind the testes, between them, in front of them, and on the dorsal 

 sides of the testes. Uterus relatively short, containing only a few 

 eggs, which are brownish in color, 32.4 ^. long by 18 pi wide. 



Host. — Lat^us t^ihundus. 



L ocation. — Intestine. 



Locality collected. — East Prussia. 



