1920] Taylor: Neuromotor Apparatus in Euplott s 405 



states, "which crosses the clear nuclear zone, emerges through the 

 nuclear membrane" whence arises a plastic thread, the rhizoplast, that 

 ends near the periphery in the blepharoplast. The two flagella grow 

 out from this blepharoplast. 



The origin of the apparatus from the centriole is not clearly estab- 

 lished. This centriole can be seen within the karyosome during the 

 entire development of the flagella, although its division may give rise 

 to these structures. Dr. Swezy (1916) offers a critical discussion of 

 this point. 



A less primitive motor apparatus is met with in Prowazekia 

 lacertae (Grassi), a parasitic flagellate found within the intestine of 

 amphibians. The form is described by Alexeieff (1912), and Janicki 

 (1915), and its motor apparatus critically compared with that of other 

 flagellates by Swezy I 1916). One stage in the life-cycle shows a motor 

 mechanism quite similar to that of the flagellated soil amoeba, including 

 two flagella attached to the blepharoplast which is connected by the 

 rhizoplast to the nucleus. This condition becomes modified by an 

 enlarged blepharoplast that elongates and buds off its larger portion 

 to form the parabasal body. The latter structure remains attached to 

 the blepharoplast by a rhizoplast and so shares a part in an integrated 

 motor apparatus that is typical for several other forms of the series. 

 The parabasal body is described in some protozoological literature 

 under the name "kinetonucleus. " Protozoologists using this nomen- 

 clature designate the nucleus "trophonucleus. " The former is held 

 to be a product of the latter, is composed of nuclear chromatin, and 

 divides mitotically. But more recent researches do not substantiate 

 these claims (Doflein. 1911. Kofoid. 1915, Swezy, 1916). The origin 

 of the body, as in Prowazekia lacertae, from the blepharoplast to 

 which it remains attached, is a fact which in itself establishes the 

 structure as a component of the motor mechanism. In this relation 

 it has been regarded as an accessory kinetic reservoir which supplies 

 oxidizable material to the locomotor organelles (Kofoid and Swezy, 

 1915). 



In Trypanoplasma congri (Martin. 1913), occurs a further com- 

 plexity in the motor apparatus with the attachment of a trailing 

 flagellum to the body by a fairly well developed membrane. It is also 

 significant that the parabasal body is here considerably elongated, 

 extending from near the blepharoplast lateral to and beyond the 

 nucleus. These variations are regarded (Swezy. 1916) as represent- 

 ing a step in the evolutionary series toward the conditions that obtain 



