Comparative account of the merocysts seen in the Himalayan flying squirrels, with a note on the identity of the parasites

Abstract

Merocysts in P. inornatus are found in the liver, spleen and lungs, while in P. magnificus the liver is the only site. In the former the protoplasmic rim is narrow and the merozoites are sparsely distributed within it; in the latter the protoplasmic rim is irregular, quite thick and broken in places. In the former, the colloidal mass is scanty, and is in the form of tenuous matrix enclosing irregular interspaces; in the latter form, the colloidal mass is in the form of homogeneous substance with little vacuolation. In view of the wide differences in the structure and the site of occurrence, the merocysts found in the two different species of flying squirrels are considered to belong to two separate parasites. The parasite occurring in P. inornatus is identified as H. rayi rayi Tokura & Wu, sensu stricto, while the other parasite occurring in P. magnificus is designated H. rayi wui, a new subspecies, named in honour of Dr Wu Chen-Lan who worked on flying squirrel malaria in Formosa.