Thomas's (ESophagostome. 51
their upper third and bent inwards. Spicules 1'38 mm. to 1"475 mm. long, at the end slightly sharp.
Females 16 to 20 mm. long, 900/a wide. Caudal extremity abruptly attenuated and terminated by a small conical appendix, occasionally turned up towards the dorsal face. Anus at about •250/x from the posterior extremity ; vulva at 500-525/x ; these two orifices not giving rise to any tegumentary protuberance. Ovojectors very near ; uterus very short, in the shape of an oblong, a little bent.
None of the females examined contained any eggs. In short they were immature forms.
If from, the foregoing description we try to determine the relations of this CEsophagostome, one is led first and foremost to eliminate the forms, the crowns of which comprise only a small number of lamellae, such as the (Esophagostomum hrumpti, Railliet and Heney, 1906, which is also a parasite of man.
A closer comparison associates it on the other hand, with the forms possessing crowns with numerous lamellae. One of these attracted our attention at once, namely, the (Esophagostomum dentigerum of the chimpanzee, which we described in 1906, of which the dimensions, the oesophagoid armature, the length of the spicules agree in a striking manner with the peculiarities observed in the Brazilian parasite.
We suspected besides a similar relationship between the latter and the (Esophagostomum Stephanostomum (Stossich) 1904 of the gorilla. Stossich's too summary description unfortunately did not allow of our pronouncing an opinion on this point. But thanks to the kindness of Messrs. Shipley and Leiper, we have been able to examine the specimens which have served as types to the
