922.] H. A. Baylis and R. Daubney: Parasitic Nematodes. 337 



This genus appears to form a link between the subfamilies Ancylostominae and 

 Necatorinae. 



Subfamily NECATORINAE, Lane, 191 7. 



Genus Necator, Stiles, 1903. 



Necator americanus (Stiles, 1902). 



We have to record the occurrence of this species in a new host, viz. a young 

 African rhinoceros * (R. bicornis), which had lived in the Zoological Gardens, Calcutta 

 for a very short time. The animal was captured in the Tanganyika Territory 

 (formerly German East Africa) and was brought to India by Mr. E. W. Harper, to 

 whom we are indebted for this information. 



Careful comparison of this material with specimens of Necator americanus from man 

 in the collection of the British Museum reveals no difference except that the female 

 specimens from the rhinoceros are slightly the longer. They measure from 11 to 13 

 mm. in length and 0*4 mm. in thickness, as against 10 to 12 mm. and 0^4 mm. res- 

 pectively in the case of the specimens from man. 



Tue subfamily Necatorinae was proposed by Lane (1917 a) to replace the older 

 subfamily Bunostominae, Looss, 1911. The difference between these two groupings is 

 that, according to Lane, the genus Uncinaria approaches more nearly to the Necator 

 and Bunostomum group than to the Ancylostominae, among wmich it was placed bjr 

 Looss. It is interesting to recall that of the subfamily Necatorinae, if TJncinaria be 

 left out of account, all the members except Necator occur in herbivorous animals 

 only,' and, in consequence, the occurrence of Necator in the rhinoceros is not so asto- 

 nishing as it might appear at first sight. All the species of Ancylosloma occur in 

 carnivores, and all except Ancylostoma duodenale and A. ceylanicum in carnivores only. 

 It seems probable, therefore, that the original hosts of the species now found in man 

 were carnivores. It is also almost certain that Necator americanus was introduced 

 into America with the African slaves, and if this is the case, man may have acquired 

 his earliest infestations with this parasite from some wild herbivore inhabiting Africa. 



Family TRICHOSTRONGYLIDAE, Leiper. 1912. 



Subfamily TRICHOSTRONGYLINAE, Leiper, 1908. 



Genus Haemonchus, Cobb, 1898. 



Haemonchus contortus (Rud., 1803). 



This species occurred in the Markhor (Capra falconeri) in the Zoological Gardens, 

 Calcutta. 



Haemonchus cervinus, sp. nov. 



The collection includes several females of a species of Haemonchus from a spotted 

 deer (Cervus axis). The specimens are in poor condition. They measure from 13 to 



1 Since the preparation of this paper, Necator has been recorded from the pig in Trinidad (Ackert and Payne, Amer. 

 Jl. of Hyg., II, 1, Jan., 1922). The authors regard the form found in pigs as a new species, which they have named 

 N . suillus. 



