154 ZOOLOGY 



cell inclusions and components, seems to us to be the most accept- 

 able working hypothesis. The degree to which one particular cell 

 organ may contribute will doubtless vary, inasmuch as the exact 

 chemical nature of the yolk, both fatty and albuminous, may vary 

 in different animals. The relative amounts of fatty and albu- 

 minous yolks has been shown to differ considerably in Helix 

 (fatty yolk 10 per cent., albuminous yolk 50 per cent.) and 

 Patella (fatty yolk 75 per cent., albuminous yolk 10 per cent.) by 

 Brambell (15). Nath has shown that of three genera of scorpions, 

 two (Euscorpius and Buthus) have albuminous yolk, and the fatty 

 yolk contains no free fat and one (Palcemnceus) has no albuminous 

 yolk, and the fatty yolk contains free fat. Such differences are 

 amply sufficient to produce appearances which will lead to 

 incorrect interpretations being put upon the processes examined. 

 A complete elucidation of these problems is evidently very far 

 off, but it seems to us that this is a likely line of attack now 

 that microchemical technique has become more exact and corre- 

 spondingly useful. 



MISCELLANEOUS 



Protozoa. The most outstanding morphological discovery in 

 the Protozoa is that of the neuromotor system. This was origin- 

 ally described by Sharp in Diplodinium ecaudatum as early as 

 1914 (116). But it was not until 1920 that an experimental 

 demonstration was given by Taylor (124) of its true nature and 

 function. Since then many workers (chiefly at the University of 

 California), such as McDonald (82), Rees (115), Campbell (18, 19), 

 Pickard (111) and Visscher (129) have found similar systems in a 

 large number of Ciliates belonging to widely divergent orders. 



A striking feature is the great similarity in broad outline of 

 these systems in the different forms. In general terms the 

 neuromotor apparatus consists of a central " motorium " situated 

 below the pharynx, from which radiate fibres to different parts of 

 the cell, but most particularly to the membranelles and specialised 

 ciliary structures. At the bases of such locomotor organs can be 

 found the basal granules of the ciliary fibres, and to these are 

 attached the " nerve fibres " from the motorium. Taken together, 



