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Marvels of the Universe 



rimlo liul [II. ,V. Climi-iil. 



A PARASITE OF THE DUCK. 



Showing the egg-case attached to a 

 hair. 



Horn}' skin^ or integuments are, indeed, of no avail against 

 the depredations of parasites armed with complete sets of 

 surgical instruments for the express purpose of penetrating 

 them. Fishes, and even the great whales of the deep, 

 likewise, serve as hosts for many parasitic organisms. 



Remarkable as it may seem, monkeys probably approach 

 the nearest to freedom from external parasitic visitors. 

 They are not infested by fleas ; and pediculi, or lice, are 

 but very rarely found upon them. That they often appear 

 to be cleaning their fur (or perhaps more often that of 

 their nearest neighbour) from these pests is true, but 

 observation has shown that they remove only bits of scurf 

 and similar secretions from the skin. " Indeed, it is this verj^ 

 habit of picking particles from the coat of each other by 

 means of their sensitive fingers and opposable thumb that 

 has prevented parasitic organisms from establishing them- 

 selves upon them as permanent and specialized species. 



Other animals, which have only been able to scratch and 

 rub themselves when attacked, have become hosts to numer- 

 ous species, some of which are so specialized as to become 

 their own particular parasites, preying on no other hosts. 

 Birds are animals which present numerous instances of that character, many species possessing 

 quite distinctive parasites ; while other parasitic organisms will prey upon only nearly related 

 bird species. On the other hand, canaries and fowls entertain mites and parasites of a more catholic 

 taste, which often make excursions to the persons having charge of these birds. 



It follows, therefore, that when a parasite is found on an animal it does not necessarily mean 

 that it is the natural parasite of that animal ; that is a point which needs careful study. 



Not infrequently parasites lose their way, and having introduced themselves to the wrong host, 



they then are compelled to use the latter as a waiting-room, 

 as it were, in the course of their travel until the train thej' 

 require comes along. Very often they never again meet 

 with their true host, and consequently they live but a 

 short time. 



Domestic poultry have perhaps more than a fair share 

 of parasites ; yet, as the accompanying illustrations show, 

 distinct species patronize the fowl, the duck, the goose, 

 and the pigeon. When we see a fowl taking a sand 

 bath, we observe it adopting an alleviative against the 

 vermin which are annoying it, the sand serving to dis- 

 lodge its visitors. Also, the fowl is not by any means 

 confined to one kind of parasite ; it harbours at least 

 eight nearly-related species of the organisms known as 

 Bird Lice, which swarm among its feathers and are often 

 left on the hands of those who have to do with it. Neither 

 are they easily brushed off, for, in common with many 

 parasites, they possess fiat and highly-polished bodies 

 which offer scarcely any resistance to touch, and they 

 can also chng very tenaciously. 



Quite apart from these insect parasites, fowls are 



mm 



Photo byl 



IB. S. dieaiiii. 



A PARASITE OF THE FOWL 



The fowl, however, is the host c 

 more than one species of parasite, ha 

 touring eight varieties of Bird Lice. 



