33 



OBSERVATIONS ON THE ENSHEATHED LARVAE 

 OF SOME PARASITIC NEMATODES. 



By T. GOODEY, D.Sc, 



Hehninfhologieal Department, London School of Tropical Medicine. 



(With 1 Text-figure.) 



Introduction 



Material 



Cultivation of the larvae 



Attempts at skin infection 



Effects of temperature 



CONTENTS. 



PAGE PAGE 



33 Resistance to desiccation and effect 



34 of plasmolysing solutions . . 43 

 34 Nature of the sheath . . .45 

 36 Summary ..... 46 

 42 References ..... 47 



INTRODUCTION. 



At the suggestion of Professor R. T. Leiper I took up the investigation 

 of the larvae of certain parasitic nematodes. Graphidium strigosum, and 

 Trichostrongylus retortaeformis, occurring in the alimentary canal of the 

 rabbit, were selected because the host is a convenient laboratory animal 

 and because the parasites are of some economic importance in causing 

 disease amongst wild rabbits. Moreover, both worms belong to the order 

 of Trichostrongylidae of w^hich many members are parasitic in the ali- 

 mentary tract of cattle, sheep and other domesticated animals. 



One of the chief objects of the research was to discover whether the 

 ensheathed larvae of these two species can infect through the skin in 

 a like manner to the ensheathed larvae of Ancylostoma duodenale, 

 Necator americanus, Strongyloides stercoralis and some others. The work 

 on N. a7nericanus recorded in the following pages arose from the necessity 

 of conducting experiments with larvae known to be skin penetrators. 

 With regard to the location of the two rabbit parasites, G. strigosum 

 occurs only in the stomach, whilst T. retortaeformis is found mostly in 

 the small intestine but may occasionally occur in the stomach also. The 

 former is reported only from rodents, but the latter has been found in 

 sheep and goats in addition to rodents. 



Ann. Biol, ix 3 



