RECENT ADVANCES IN SCIENCE 399 



water which had its salinity reduced by continuous dilution. 

 It was found that these animals were capable of a certain 

 amount of adaptation, becoming more and more active, larger, 

 more flexible, and exhibiting a marked shortening of the feed- 

 ing cirri. 



Invertebrata. — Papers include : 



Gemmil, " Ciliary Action in the Internal Cavities of the Ctenophore Plcuro- 

 brachia pilcus" {Proc. Zool. Soc, Pts. Ill and IV, March 1919). 



Faust, in a series of three papers — " Notes on the Excre- 

 tory System of an Amphistome Cercaria convoluta nov. spec." 

 (Biol. Bull., vol. xxxvi, April 19 19) ; " The Excretory 

 System in Digenea : II, Observations on the Excretory System 

 in Distome Cercarise " (ibid., May) ; and " III, Notes on the 

 Excretory System in a Monostome Larva, Cercaria spatula 

 nov. spec." (ibid.) — deals particularly with the flame cells. 

 They are important since their group plan is indicative of at 

 any rate sub-family relationship. A fundamental homology 

 exists between the excretory system of both redia and cercaria 

 generations. 



Other papers include : 



Thompson, " Association of Somatic and Germ Cells in Cestodes " {Biol. 

 Bull., vol. xxxvi, May 19A9), and "The Degeneration of Yolk Glands and Cells in 

 Cestodes" {ibid.); Drew, "Sexual Activities of the Squid, Loligo pealii (Les.) : 

 II, The Spermatophore : its Structure, Ejaculation, and Formation" {Jour. 

 Morph., vol. xxxii, June 1919); and Essenberg, "The Pteropod Desmopterus 

 pacificus sp. nov." {Univ. of California Publ. in Zool., May 1919). 



Much work has been done on the embryology of the Insecta, 

 but it is in the main confined to the stages after the formation 

 of the germ-band. In " The Formation of the Germ-Band in 

 the Egg of the Holly Tortrix Moth, Eudemis nmvana (Hb.) " 

 (Proc. Roy. Soc. Edin., vol. xxxviii, 1918), Huie describes the 

 earlier stages in this Lepidopteron. It is a particularly for- 

 tunate species to take, since the egg is long and flattened and 

 transparent, so that the processes can be followed in the living 

 animal, thus enabling the author to fill in a gap in our know- 

 ledge of early insect development. 



Other papers include : 



Baumberger, " A Nutritional Study of Insects, with Special Reference to 

 Micro-organisms and their Substrata " {Jour. Exper. Zool., vol. xxviii, April 

 1919) ; and Bridges, "The Genetics of Purple Eye Colour in Drosophila melano- 

 gaster" {ibid., May 19 19). 



Vertebrata. — The papers include : 



Day, " The Physiology of the Nervous System of the Tunicate : I, The 

 Relation of the Nerve Ganglion to Sensory Responses " {Jour. Exp. Zool., 

 May 19 19). 



