DR. R. T. LEIPER ON NEMATODE PARASITES. 



EXHIBITIONS AND NOTICES. 



April 4, 1911. 



Dr. Henry "Woodward, F.E,.S., Yice-Presiclent, 

 in the Chair. 



Sir E. Ray Lankester, K.C.B., F.R.S., F.Z.S., exhibited a 

 special Supplement of the ' Field ' newspaper dealing with the 

 British non-migratory Trout, and called attention to this new 

 medium for the publication of scientific observations requiring 

 illustrations. 



Dr. R. T. Leiper, F.Z.S., gave a demonstration of Nematode 

 parasites obtained from animals in the Zoological Gardens during 

 the year ending Nov^ember 1910. 



The collection contained a number of new forms, of which a 

 systematic account will be published later. Among the nioie 

 intei-esting of the known forms were Rictularia jdagiostoma 

 from a Palm-Oivet, a number of species of PolydelpMs from 

 various Pythons, DicheUonema horrida from the South American 

 Ostrich, and Dictyocaulus filar ia from the lungs of Sheep. 



It was noticed that whereas intestinal parasites were almost 

 wholly collected from animals that had not lived in the Gardens 

 for more than six months, those of which the normal habitat and 

 food were the internal tissues of the host occurred in animals 

 that had been confined in the Gardens for several years. Thus, 

 an undescribed Filaria was found in a Lemur after four j'ears', 

 and Filaria auslralis in a Wallaby after two and a half yeai's' 

 captivity. 



In all these cases the number of parasites obtained was small, 

 and could have had little or no effect upon the health of the 

 host. There was a remarkable preponderance of female forms. 



Fi'om these observations it appeared that the change of food 

 and general conditions obtaining in the Gardens were unfavourable 

 to the continued existence of the intestinal pai'asites an animal 

 may liarbonr on its admission. The number of cases of auto- 

 and re-infection during captivity was strikingly small, and boie 

 testimony to the cleanly surroundings in which the animals were 

 kept. In four cases only was there evidence of the occurrence 

 of accumulative infection in the Gardens : — 



1. A number of Giant Toads died from lung infection with 



Rhahdias hvfonis. 



2. The Wolves appeared to be heavily infected with Ascaris 



canis. 



3. A Sheep died from pneumonic condition resulting from 



an intense infection with Dictyocaulus filaria. 



4. The Tortoises had Oxjairiasis. 



In all these cases repeated infection undoubtedly had followed 



