i74 SCIENCE PROGRESS. 



with one another by a number of cells of an intermediate 

 character. Goette's figures, too, are by no means con- 

 vincing that what he letters ectoderm is not really endo- 

 derm or vice versa. 



The controversy is an interesting one, and will doubt- 

 less be carefully followed by those who are studying this 

 group of Ccelenterates, but it is not possible to say at 

 present that very much progress has been made. 



Passing on to the group of the Protozoa, we find very 

 few papers that have excited very general interest. The 

 well-known eye spots of the Flagellata have recently been 

 subjected to a careful examination by Franze. 1 Each 

 of these organs consists of a mass of pigment of various 

 shapes, and one or more transparent lens-like bodies, 

 lying in or on it. A careful study of the chemical re- 

 actions given by these lenses shows that in some cases, 

 such as the Euglenidae, they are composed of paramylum ; 

 and in others, such as the Chlamydomonads and Volvo- 

 cinese, they are composed of amylum. Their development 

 is dependent upon the metabolic activity of the organisms, 

 and the author found that after Euglenae had been kept 

 in the dark for some time, the size and number of their 

 lenses were considerably reduced. This he attributes to 

 the diminished metabolic activity in the dark of the 

 chlorophyll bearing Flagellates. He also observed that 

 those species of Euglena which naturally possess few par- 

 amylum granules show either no lenses or very few in 

 their clear red eye spots. 



As a great deal of attention has been paid recently to 

 all matters dealing with the minute structure, and the 

 phenomena accompanying the division of the nuclei of 

 cells, Rhumbler's 2 account of those curious bodies, usually 

 considered to be nucleoli, which occur in the nuclei of many 

 Protozoa, will be read with much interest. 



1 Franze, R., Zur Morphologie und Physiologie der Stigmata der 

 Mastigophoren, Z. f. wiss. ZooL, lvi., part ii. 



2 Rhumbler, L., " Ueber Entstehung und Bedeutung der in der 

 Kernen vieler Protozoen und in Keimblaschen von Metazoen vorkom- 

 menden Binnenkorper (Nucleolen)," Zeitschr. f. wiss. ZooL, lvi., part ii. 



