904 PROTOZOA AND OTHER ANIMALS 



present in tadpoles. This differs from the type in several respects, the 

 most important being the lack of a stigma and the presence of from two 

 to six flagella. Most frequently there are from four to six flagella. Ac- 

 cording to Wenrich, six is the doubled number, three new ones growing 

 out very early in preparation for division. In other numbers above three, 

 there are various stages of outgrowth. Division of a flagellate with four 

 flagella results in daughter flagellates with two. 



Brumpt and Lavier (1924) considered Wenrich's colorless variety to 

 be a separate species, and Wenrich (1935) seemed inclined to the same 

 opinion. Brumpt and Lavier described a similar colorless form with no 

 stigma, from tadpoles of Leptodactylus ocellatus at Sao Paulo, Brazil, as 

 Hegneria leptodactyli. That flagellate has seven flagella ordinarily, but 

 may have only six. The authors did not mention the presence of an 

 accompanying green form with fewer flagella, and Wenrich (1935) 

 stated that he found the colorless flagellate in some hosts, unaccompanied 

 by the green one. The six-flagellated forms of Hegneria seem to resemble 

 very closely the six-flagellated forms of Euglenamorpha hegneri var. pel- 

 lucida, so that it may be necessary to revise the taxonomy of the flagel- 

 lates. 



One is tempted to find, in this interesting series of forms, as Wenrich 

 has brought out, adaptation to the conditions of an endobiotic habitat in 

 loss of chloroplasts and increase of the number of flagella. 



Endozoic colorless euglenid flagellates of the Astasia type have often 

 been found, especially in Turbellaria, but also in rotifers, Gastrotricha, 

 fresh-water nematodes, fresh-water oligochaetes, nudibranch eggs, and 

 copepods. They usually are in vigorous metabolic movement, and gen- 

 erally lack a flagellum when in the host. 



Haswell (1892) found them abundant in parenchymal cells in all 

 specimens examined of a rhabdocoele turbellarian in Sydney. A flagellum 

 was present in many but not in most cases. No stigma is mentioned. In 

 1907 Haswell described a similar euglenid in many specimens of an- 

 other rhabdocoele, within cells of the digestive epithelium and in the 

 spaces between the gut and the body wall. In the host, it was motion- 

 less or executed slow movements, but was more active when freed. No 

 flagellum was present until two hours or more after the organisms were 

 freed from the host. They were kept alive outside of the host for several 

 days, but no euglenids were found normally free in the water. 



