Various species of Trypanosoma from the blood of mammals, birds, and reptiles. A. T. Lewisii, from the blood of rats; B. T. Brucei, the parasite of the Nagana or Tsetze-fly disease, found in the blood of horses, cattle, and big game; C. T. gambiense, the parasite causing Sleeping Sickness in man; D. T. equinum, which causes the mal de caderas in South American horse ranches; E. T. noctuæ, from the blood of the little owl, Athene noctua; F. T. avium, found in the blood of many birds; G. a species found in the blood of Indian pigeons; H. T. ziemanni, a second species from the blood of the little owl; J. T. damoniæ, from the blood of a tortoise; c.g., granules; v., vacuole; l.s., fold of the crest or undulating membrane.