Volume VIII 
SEPTEMBER, 1915 
No. 2 
THE LIFE HISTORY OF NEMATODIRUS FILI- 
COLLIS RUD., A NEMATODE PARASITE OF 
THE SHEEP’S INTESTINE. 
By CHARLES L. BOULENGER, M.A., D.Sc. 
Reader in Helminthology, the University of Birmingham. 
(From the Research Laboratory in Agricultural Zoology, University of 
Birmingham.) 
(With Plates VIII and IX and 5 Text-figures.) 
CONTENTS 
Introduction ...... 
PAGE 
133 
Historical ....... 
135 
Specific Diagnosis ..... 
137 
The Egg . 
138 
Development of the Egg outside the Host . 
139 
The Hatching of the Embryos 
141 
Description of the “Ensheathed” Larva 
142 
The Biology of the “Ensheathed” Larvae . 
145 
The Completion of the Second Ecdysis 
147 
Structure of the “Exsheathed” Larva . 
149 
Mode of Infection of Sheep .... 
150 
Young Stages in the Sheep .... 
150 
Summary of Life History .... 
152 
References ....... 
153 
Explanation of Plates ..... 
154 
Introduction. 
Sheep are probably more frequently affected by diseases due to 
parasitic worms than any other of our domestic animals, and of Nema¬ 
todes alone at least twenty-eight species have been recorded from the 
alimentary tract, chiefly from the fourth stomach (abomasum) and the 
intestines. 
Parasitology vm 
9 
