a1 From The Molteno Institute for Research in Parasitology, Cambridge.
A Previous paper (Bishop, 1932) dealt with the cultivation of a Hexamita sp. found in the horse-leech (Haemopis sanguisugae = Aulastomum gulo). The present paper deals with the morphology and method of division of the Hexamita above referred to, which I now name H. gigas n.sp. Dobell (1909) gave a detailed history of the nomenclature of the genus, and Wenyon (1926) has dealt with the same subject and given a list of the then known species and their hosts. Two species have since been described: H. pulcher, by Becker (1926), from the caecum of the ground squirrel Citellus tridecemlineatus, and Octomitus (= Hexamita) pitheci described and figured by da Cunha and Muniz (1928) from the intestine of Macacus rhesus. Apart from the two species (Hexamita nodulosa and H. inflate) described by Dujardin (1841) from stagnant water, and in which he saw but six flagella, a single species only has been described hitherto from a non-vertebrate host. This species, Octomitus (= Hexamita) periplanetae, a small flagellate 5–8 μ in length, from the gut of the cockroach, was described by Bělař (1916); a similar flagellate from the gut of Blatta orientalis has been found by me.
(Received December 10 1932)
1 A study begun during my tenure of a Beit Memorial Fellowship and completed since I became a Yarrow Fellow.
Former Beit Memorial Research Fellow, Yarrow Fellow of Girton College.