. Protozoo?logy. Protozoa; Protozoa, Pathogenic. THE GENUS TRYPANOSOMA 247 anterior flagellum and elaboration of the lateral protoplasm into an undulating membrane. According to such a derivation, the flagellated end of a trypanosome would be posterior, and this is the view taken by a number of authorities. As Minchin ('08) points out, however, the developmental history of no trypanosome points to this mode of origin, but tends rather to support the second hypothesis of the origin of trypanosomes from herpetomonas and crithidia-like forms by the posterior migration of the kinetonucleus and ble
. Protozoo?logy. Protozoa; Protozoa, Pathogenic. THE GENUS TRYPANOSOMA 247 anterior flagellum and elaboration of the lateral protoplasm into an undulating membrane. According to such a derivation, the flagellated end of a trypanosome would be posterior, and this is the view taken by a number of authorities. As Minchin ('08) points out, however, the developmental history of no trypanosome points to this mode of origin, but tends rather to support the second hypothesis of the origin of trypanosomes from herpetomonas and crithidia-like forms by the posterior migration of the kinetonucleus and blepharoplast, whereby these structures become secondarily posterior, while the flagellum Fig. 99. Trypanosoma noctuae. (After Schaudinn.) Schematic representation of the metamor- phosis of a fertilized cell into an "indifferent" type of Trypanosoma. F, G, H, formation of the undulating membrane and flagellum from kinetoplasmic material, would be attached to the cell, as in herpetomonas, at the anterior end. Schaudinn has shown that the flagellum in Trypanosoma noctucB has this mode of origin, and grows out from the anterior end, while the kinetonucleus and blepharoplast (Fig. 99) remain anterior to the nucleus. In other species, however, the developmental history shows that young forms and culture forms are similar to crithidia with rudimentary membrane and anterior blepharoplast and kinetonucleus. This is well described in the case of a trypanosome of the ray, Try- panosome raico (?), by Robertson ('07). Here in young forms, after division in the gut of the leech Pontobdella muricata, the kinetonucleus. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Calkins, Gary N. (Gary Nathan), b. 1869. New York and Philadelphia, Lea & Febiger
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