146 Veterinary Medicine. 



These are acarina with free filiform palpi. 



Gamasus Pteroptoides found in the fur of field mice, moles and 

 rabbits is characterized by a small rostrum, styliform mandibles, 

 large limbs, equal in the two sexes, and terminated by claws and 

 caruncle. About 0.5 mm. long. They live on the exudations 

 and do not appear to be hurtful. 



Gamasus Auris found by Turnbull in great numbers in the 

 external auditory canal of the ox as deeply as the tympanic mem- 

 brane, is suppo,sed to have been a wanderer from forage in which 

 the gamasidse are largely represented. 



Dermanyssus Gallinse. D. Avium. This is pyriform, 

 broadest behind, flattened from above downward, hairy yellowish 

 white when fasting (among manure), blood-red when gorged (on 

 skin), female 0.7 mm.; male 0.6 mm. long. 



Habitat. Pathogenesis. During the day these are found in 

 neglected and filthy hen houses, poultry yards, dove cots, etc., 

 among the manure, and in cracks and fissures in the wall, floor 

 and perches, also in the nests. At night they become extremely 

 active getting upon the birds and sucking their blood, banishing 

 sleep, causing anaemia, emaciation and weakness, and even driv- 

 ing the sitting birds from their nests : Dermanyssus Acariasis. 

 In the same way they make nightly attacks on horses, cattle and 

 other animals kept in the same buildings with the fowls cr near 

 to them : Poultry Acariasis : Poultry Lousiness. This leads 

 to intense itching, rubbing, loss of hair, and the formation of 

 abrasions, sores, scurfy productions and scabs, the cause of which 

 may not be apparent. Enquiry will .show that they live near 

 fowls, and a visit after nightfall will reveal the presence on the 

 skin of myriads of the blood sucking dermanyssus. Human 

 beings, who frequent the poultry houses are attacked, also those 

 that pluck the fowls, or handle the feathers or manure. Usually 

 they cause in man but a temporary pruritus, unless the exposure 

 continues day after day. Goldsmith, however, cites the case of a 

 woman with a chronic skin di.'iease, on whose skin the acarina 

 appeared on the surface during perspiration, but retired into the 

 cutaneous gland ducts in the intervals. 



Poultry Otacariasis and Rhinacariasis. Zurn and Webber 

 have found this dermanyssus colonized in the nasal chambers of 

 poultry and pigeons cauising an acute nasal catarrh, and lyax has 



