Abstract
1. It is proved by the infestation experiment with dogs that Gymnopleurus sinnatus is the intermediate host of Sp. sanguinotenta in the vicinity of Mukden, its larvae especially invading the wall of aorta.
2. Rabbits, if fed with lanolin or lard, also can be infested with larvae of the present parasite forming aneurysma, but these larvae can not develop to their mature stage in this improper host, being entirely destroyed within 4 months after infestation. Rabbits fed with the normal diet can not contract infestation with Sp. sanguinolenta.
3. The broken elastic lamellae are detected in the preparation from the invaded tissue of aorta stained with Weigert's fuchsin-resorcin solution.
4. The larvae of Sp. sanguinolenta, as the adults do, also carry the blood-colored fluid in their body cavities even 1 day after infestation.
5. It is deduced from various points of view that the parasite from Bl. orientalis pointed out as Sp. sanguinolenta by Grassi is in all probability one of allied species (Spirura sp.?).
I tender my warm thanks to Dr. K. Kasai, Director of the Institute, and to Prof. S. Yoshida for their cordial guidance.
