346 PARASITES OF ANIMALS 



f erred to the bodies of setigerous annelids, which are thus called 

 upon to act as intermediate hosts. If this be so, it is further 

 certain that important structural changes with ecdysis follow 

 after their escape from the earth-worms or other annelids, 

 moisture, dew, or water being essential to the penultimate 

 stage of growth. Final passive transference, either with 

 fresh fodder from swampy grounds, or, it may be, from pond 

 water, ultimately enables them to acquire their definite sexual 

 form, size, and other adult characteristics. 



According to Megnin it is not the Strongylus filaria, but a 

 hitherto unknown and totally distinct species (Strongylus minu- 

 tissimus) which occasions pneumonia in Algerian sheep. In 

 England the parasitic bronchitis affecting sheep is generally 

 called the "lamb disease." This is unfortunate, because many 

 other parasites prove destructive to lambs. One of the most 

 injurious species is Strongylus contortus, infesting the true 

 stomach, whilst 8. hypostomus, occupying the small intestines, 

 is almost equally obnoxious to the ovine bearer. By Leuckart 

 and others this last-named worm is retained in Dujardin's genus 

 Dochmius, in which genus another species occurs (D. cernuus). 

 This worm is quite distinct, but not readily distinguishable by 

 the naked eye alone. It occasionally occupies the upper part 

 of the colon, as well as the lower end of the small intestine. 

 A rarer intestinal worm in lambs is the Strongylus filicollis. 

 Several other stron gyles infest the ox (S. radiatus, 8. inflatus, 

 S. gigas), goat (S. venulosus), and stag (S. ventricosus) . 



As showing the extraordinary prevalence and destructiveness 

 of entozoa in certain countries, I will adduce an instance in 

 which my opinion was requested and given some five years 

 since. My informant stated the case somewhat in the following 

 manner : On a farm in New South Wales, and lying about 200 

 miles to the north-west of Sydney, on the Trafalgar tributary 

 of the Macquarie river, out of a flock of about 8000 sheep no less 

 than 1200 have perished. In many instances post-mortem 

 examinations were made, worms appearing in all cases to be the 

 cause of death. There were four kinds of parasites present. 

 The most numerous were red and white, fe marked like a 

 barber's pole." These occurred chiefly in the fourth stomach 

 and commencement of the duodenum, but some were found 

 throughout the entire length of the small intestine. A second set 

 comprised small black worms, resembling needles, scattered only 

 in the lumen of the intestines. The third set were tapeworms, 



