4I4 SCIENCE PROGRESS 



and it is such observations which for the most part have still 

 to be made. 



ZOOLOGY. By Chas. H. O'Donoghue, D.Sc, F.Z.S., University College, 

 London. 



Protozoa. — The papers include " Observations on Blastocystis 

 Hominis " by Swellengrebel {Parasit. July 17) and " Observa- 

 tions on Entamoeba gingivalis from the Human Mouth, with a 

 note on the Trichomonad Flagellate Tetratrichomonas buccalis," 

 by Goodey and Wellings (ibid.). 



Invertebrata. — Stephenson has furnished a useful paper 

 " On the So-called Pharyngeal Gland-cells of Earthworms " 

 (Quart. Jour. Micro. Sci. vol. 63, August 17). These cells are 

 not gland-cells in the ordinary sense of the word, and do not 

 communicate with the pharynx ; it is therefore proposed to call 

 them " chromophil cells." They contain an unequally dis- 

 tributed deeply staining substance and are incompletely covered 

 with a sort of capsule of flattened cells. " The cells are to be 

 looked on as of peritoneal origin ; that is to say, they are 

 modifications of the original lining cells of the ccelonic cavity. 

 Hence the absence of a capsule in the early stages ; and hence 

 the original limitation of the cells to the superficial portion of 

 the pharyngeal mass. The main function of the cells is prob- 

 ably metabolic." 



Other papers include : " Some Cestodes from Japanese 

 Selachians, including Five New Species," by Yoshida (Parasit. 

 July 191 7), and " Sur Quelques Nematodes des Oiseaux de la 

 Russie," by Skrjabin (ibid.). 



" Notes on Asteroidea " and " A New Genus and Sub-genus 

 of East Indian Sea Stars," both by Fisher (Ann. and Mag. 

 Nat. Hist. August 17), and " Multiplication by Fission in Holo- 

 thurians," by Crozier (American Nat. September 17). 



Cameron has carried out an intensive study of " The Insect 

 Association of a Local Environment Complex in the District of 

 Holmes Chapel, Cheshire " (Trans. Roy. Soc. Edin. vol. lii. 

 April 17), and he summarises his observations as follows : "In 

 any given 4 locality the composition of insect association is 

 determined by a complex of factors, which may be classified 

 as follows, viz. physical, physiographical, topographical and 

 vegetational. Primarily it is dependent upon the ecological 

 type of the vegetation." An enumeration of the insects 



