* 
C. L. Boulbnger 
Oesophagus: 1-6-2*4 mm. in length. The cervical papillae are in the 
neighbourhood of the nerve-ring, about 1*5 mm. from the anterior extremity 
of the body. 
Female : 30-42 mm. in length, 1-8-2-5 mm. in extreme breadth. The head 
has a width of 0-9-T3 mm. 
Vulva 6-7 mm. from the posterior end of the body. The tail region is 
similar to that of S. equinus and S. edentatus\ the anus is 0-4-0-6 mm. from 
the posterior extremity. 
Male : 18-32 mm. in length, with a maximum breadth of about V8 mm. 
The head is 0-6-0-9 mm. broad. 
As in the two larger of the known species of Strongylus the genital bursa 
is small as compared with the size of the body, it measures VI in width in 
the largest specimen before me. The median lobe is short (Fig. 2). 
Fig, 1. Strongylus asini sp. n. A. Dorsal view of anterior extremity, x 37. B. Lateral 
view of anterior extremity of another specimen, x 37. 
The rays of the bursa are similar to those of S. edentalus, i.e. they are more 
slender than those of S. equinus. The branches of the posterior rays differ 
from those of the other species in that the inner (dorsal) branch is simple, 
the external branch divided^ i.e. the converse of the arrangement prevailing- 
in the genus. This character may however not be specific. I was able to 
examine three male specimens only and the mode of branching of the posterior 
rays is liable to variation in many species of Strongyles. The spicules measure 
approximately 1-6 mm. in length. 
Habitat : (1) Zanzibar, in a cyst of the liver and in the caecum of the donkey. 
(2) Nairobi, East Africa, in the caecum of the donkey. 
The Zanzibar specimens consisted of three females and one male (all fully 
developed) from the liver cyst, whilst another male was found among a number 
of specimens of S. edentalus and S. vulgaris from the caecum. The Nairobi 
