904 SUMMAEY OF CURRENT RESEARCHES RELATING TO 



interior ; they exhibit a distinct transverse striation, and call to mind 

 exactly a muscle-fibril. The author cites a number of forms in which 

 he has observed a similar striation. In addition to these terminal 

 locomotive organs there is a group of flagella, the presence of which 

 does not seem to have been hitherto noticed; they are likewise 

 striated, but appear to serve in the prehension of food. The walls of 

 the body are made up of four layers, of which the outermost or cuticle 

 is colourless, while the rest are impregnated with chlorophyll. In 

 the deepest of these there are polygonal starch-grains, which when 

 well developed are so closely ajipressed as to give almost a reticular 

 appearance. They are so regularly arranged as to seem to be the 

 signs of a real division of the formative layer into small protoplasmic 

 spheres, each of which produces a starch-granule in its interior. In 

 the two other tegumentary layers, which are less thick, there are a 

 large number of extremely small vacuoles, filled with a watery proto- 

 plasm, and separated from one another by the delicate parts of the 

 denser substance. An analogous structure is to be seen in the 

 enveloping cuticle. 



There is no oesophageal tube, as has been described, but a spacious 

 and well-bounded stomach in which the food is digested ; the thick 

 walls of this organ present a number of granulations, regularly 

 arranged ; these are starch-granules. Where they are wanting it is 

 possible to see that the constituent protoplasm has a regularly 

 vacuolated structure, and that its irregular appearance is due to the 

 presence of these granules. An intestine and anus are also described. 

 The contractile vesicle is said to communicate with the exterior by a 

 pore, to have distinct vacuolar walls, and to give off a short canal 

 from its inferior portion. 



The nucleus is reported to be regularly and finely vacuolar and to 

 have a certain number of nucleoli ; the vesicular corpuscles frequently 

 divide transversely, and may be seen to be surrounded by a zone of 

 clear protoplasm. These the author looks upon as germs. Above 

 the stomach and to the front and right of the nucleus there is a large and 

 finely vacuolated mass of protoplasm, in which there are a number of 

 nucleolar corpuscles, and whence a tube passes to the vestibular duct. 

 This is regarded as an excretory organ or a male apparatus, and the 

 latter hypothesis is inclined to on the ground that some kind of 

 copulation has been observed in this form. 



For the purposes of studying the oculiform spot of the Flagellata 

 the author selected Phacus pleuronectes ; in individuals kept in com- 

 parative darkness the spot is feebly developed ; when placed in a 

 quantity of light the spot became large, brilliant, and very red ; and 

 the organ is reported to consist of a collection of red, irregularly 

 pyriform granulations, the internal substance being hyaline ; all the 

 granules are placed on a curve, and the corresponding concavity 

 contains a transparent, refractive, and lenticular corpuscle; so that 

 from the structural point of view the author is satisfied as to the 

 visual functions of this organ. 



The author points out that the peculiar mode of division, which 

 appears to be intermediate between fission and gemmation, is due to 



