1913.] NATURAL SCIENCES OF PHILADELPHIA. 133 



A. From (1) above, 14 per cent, of our living parrots would be 

 verminous, 20 birds. 



B. 86 per cent, of our living parrots would be non-verminous, 

 120 birds. 



Suppose at the end of the year there had been 50 deaths (average 

 for 7 years). 



C. From (2) above, 30 per cent, would be verminous, 15 birds. 



D. Then 70 per cent, would be non-verminous, 35 birds. 



From A and C — Out of 20 living verminous birds 15 deaths re- 

 sulted, 75 per cent. 



From B and D — Out of 120 living non-verminous birds 35 deaths 

 resulted, 30 per cent. 



The mortality is more than twice as great for living verminous 

 parrots than for non-verminous. 



This is one point against the innocence of Spiroptera incerta. 

 Our second witness is the autopsy picture. 



The Parasite. — It has been described in detail by Dr. Allen J. 

 Smith as a new species in his Sytwpsis of Studies in Metazoan Para- 

 sitology. Briefly, the mature female averages 14 mm. in length 

 by 0.6 mm. in diameter. It is rigid, of a dead or yellow-white color. 

 The male is distinctly smaller. They vary in numbers from two 

 to a hundred or more. The usual number is twenty or thirty. 

 They may be found in a ball of mucus in the lumen of the pro- 

 ventricle or burrowing into the mucosa. The smallest (larval) 

 forms are often found under the thick chitinous lining of the gizzard. 

 The Host.— In severe infestations the bird is emaciated. It 

 sometimes emits a wheezing sound (not pneumonia) or passes mucus 

 from mouth or nostril. Often the droppings have been abnormally 

 copious, and when mucus is admixed (as it often is) infestation 

 has been foretold. 



The Lesion. — Even where there are but a few worms (4-6) in the 

 proventricle, the swelling is prominent. Diagnosis can be made as 

 soon as the body cavity is opened. On opening the organ the mucosa 

 is found necrotic and overlaid by mucus. The worms, if pulled out 

 by forceps and relaid on the mucus promptly burrow into it and 

 disappear. Where the worms are numerous the viscus is enormously 

 distended, even exceeding the gizzard in size. The heart is pushed 

 far to the right, the gizzard placed so low as to press on the cloaca. 

 In one case a perforation had occurred, and seeds and worms were 

 found in the air sacs. On section the mucosa is necrotic, destroyed. 

 The wall of the viscus may be so thin as to be translucent. The 



