Semi-Centennial Volume. 101 



3. The shape of a typical cyclone, when appearing alone, or as a 

 projection downward from a cloud, is exactly that of the cavity of a 

 whirlpool, funnel-shaped, and is formed by the suction downward of the 

 cloud to fill what corresponds to the cavity of a whirlpool in a stream. 



4. The damage is done by the twisting rotary motion of the atmos- 

 phere, thus accounting for things being thrown in every direction, and 

 not by rapid lateral movement; for, as with the whirlpools in the stream, 

 the forward movement of a cyclone is sometimes quite slow. 



5. Cyclones, as here explained, should occur in "twins" sometimes, 

 one on either side of the rain current; and this actually did happen just 

 one week later, June 13, 1917, a few miles farther west, near Wamego. 



July 13, 1917. 



On the Transmission of the Fowl Cestode, Davainea 

 Cesticillus (Molin). 



James E. Ackert, Ka-nsas State Agricultural College. 



In the vicinity of Manhattan, Kan., a large percentage of the fowls 

 are infested with tapeworms. Of 161 chickens examined, 121, or 75.1 per- 

 cent, had tapeworms in their intestinal tracts. The infestations ranged 

 from one to two or three hundred, and in one instance a young chick 

 harbored 443 of these parasitic worms. Fourteen to twenty-seven ces- 

 todes is common, and this number usually makes a visible effect upon 

 the fowl, causing emaciation, loss of feathers, and general debility. The 

 average infestation for the 161 chickens was 26.7 tapeworms per fowl. 



Examinations of numerous poultry yards for possible intermediate 

 hosts of chicken tapeworms gave strong circumstantial evidence against 

 house flies. The latter were abundant, while other invertebrates were 

 comparatively rare. It was found that the behavior of the house flies 

 was not unlike that of the chickens. In the early morning they were 

 moving about in the sunshine, but as the heat of the day came on the 

 flies went to the shade, alighting upon the stones and the shady side of 

 buildings. The fowls likewise were actively feeding in the morning, but 

 by ten o'clock were in the shade, the young chicks pursuing flies while 

 the old birds were preening their feathers. In the shade of the poultry 

 house flies were crawling over the floor and feeding upon feces, which 

 contained tapeworm embryos. 



From fowls in the United States six different species of cestodes have 

 been collected. Of these, Davainea procjlottina, (Davaine), rare in this 

 country, may be transmitted by a slug {Umax cinerens) . Another, 

 Choanotsenia infundibuliformis (Goeze), may be transmitted by the 

 house fly, Musca domestica. The means of transmitting any of the re- 

 maining four species was not known until the past summer, when an 

 experiment demonstrated that the housefly may transmit to fowls another 

 of these cestodes, which appears to be Davainea cesticillus (Molin, 1858), 

 Blanchard, 1891. 



The fowls used in the experiment were hatched in an incubator and 

 placed at once in a fly-proof field cage, where they were given food free 

 from animal tissues, with the exception of an occasional feeding of care- 



