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PROCEEDINGS OF THE NATIONAL MUSEUM. 



VOL. 50. 



The tail (fig. 63) is straight and conical and terminates in a small 

 point comparable to that of the male. The vulva is very prominent 

 and visible to the naked eye. It opens transversely on the ventral 

 surface in the anterior portion of the body about 1/2.5 of the total 



62. 63. 



Figs. 62, 63.— Subulxtra boueti. 62, Accessory piece in anterior, a, and posterior, 6, view, and 



THE spicule, C. AfTER GENDRE, 1911. 63, POSTERIOR EXTREMITY OF FEMALE. ENLARGED. AFTER 



Gendre, 1911. 



body length from the head. The genital apparatus is double. The 

 eggs have thin shells and are rounded in shape. They average 62 fi 

 long and 52 ix wide. They contain an embryo, always rolled up like 

 a snail, in a uniform fashion, when oviposited. 



Host. — Euxerus erythropus (Xerus erythropus). 



Location. — Intestine. 



Locality. — Agouagon, Dahomey. 



As noted in the discussion of S. uncinata, there seem to be no 

 morphological differences between that species and S. houeti. 



HETEROXYNEMA Hall, 1916, new genus. 



Generic diagnosis. — Subulurinae (p. 51) : Mouth Avith three lips; 

 teeth feebly, if at all, developed at the base of the mouth. Two 

 cervical alae present. No spicules or gubernaculum visible. Pre- 

 anal sucker fusiform and without a chitinous margin, the margin 

 consisting of a delicate cuticular membrane, which is apparently 

 lacking in the median line anteriorly and posteriorly, so that the 

 sucker has two lateral cuticular membranes. The vulva is near the 

 union of the anterior and middle thirds of the body. The eggs are 

 bluntly pointed, somewhat similar to those of Oxyuris. 



Type-species. — Heteroxynerna cucullaium Hall, 1916. 



