Snowshde-rabbit 647 



digestive canal, caused by round worms. There were two 

 species of parasites present. The stomach worm, which I 

 recognized as the Strongylus strigosus, is a most dangerous 

 parasite, since it Hves by sucking the blood of its host and 

 causes death chiefly by anaemia and emaciation. This 

 parasite is blood-red in colour, about ^ to ;] of an inch in length, 

 and marked by numerous longitudinal lines from which it 

 derives its name (striped strongle). The parasites were present 

 in great numbers, many hundreds in each animal. The spe- 

 cies found in the small and large intestines I am unable to 

 identify, but since it is not a blood-sucking parasite, it is less 

 important than the stomach-worms. These worms are | 

 of an inch long and of the thickness of thin twine. 



"The oil of areca nut is the best treatment to reach these 

 worms; and the separation of infested animals and the chang- 

 ing of the runs are important matters." 



Dr. W. T. Hornaday, who took part in the investigation, 

 adds: "I examined them under the microscope with great 

 interest. They were present in very large numbers, and the 

 eggs which the Strongylus seemed about ready to put forth 

 betokened reproduction by hundreds of thousands. I think 

 the two parasites account for the periodical seven-year plague 

 among the Northern Varying-hares, and also the Rabbits of 

 the West. The life-history of Strongylus is not well known, 

 but it may easily develop that the cycle of this creature's 

 destructiveness is seven years long." 



Another specimen which died in the park in January, 1906, 

 was thus reported on by Dr. W. Reid Blair: 



"Death was due to a generalized infection with tape- 

 worm cysts. These cysts are present in enormous numbers in 

 practically all the tissues of the body, the liver, mesentery, 

 diaphragm, spleen, and pectoral muscles being most involved. 

 A multilobular cyst situated over the ribs on the left side was 

 completely encapsulated by the superficial muscles; on re- 

 moval it was found to be about the size of a duck's egg and 

 to weigh 6 ounces. This cyst contained besides 4 ounces of 

 clear fluid, about 300 heads of the tcvnia (mature), every one 



