ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 255 



Annulata. 



Taste in Leeches. — L. Lohner {Arch. f. Ges. Physiol., 1916, 163, 

 239-4G). A piece of skin folded into a funnel was filled with various 

 fluids (salt, sweet, acid, alkaline, etc.), and the leeches sucked the outer 

 surface. At a certain degree of concentration the leeches cease to suck 

 and let go. This fact was utilized to determine when a leech dis- 

 criminated between one kind of fluid and another. The limit was 7 p.c, 

 for common salt, 5 p.c. for cane-sugar, 0*08-1 p.c. for sulphate of 

 quinine, • 08-0 • 09 p.c. for caustic potash, and so on. When two liquids 

 different in taste were mixed the gustatory sensitiveness was lessened, as 

 iu man. J. A. T. 



Platyhelminthes. 



Action of Potassium Cyanide in Planaria. — L. H. Hyman {Amer^ 

 Journ. Physiology, 1919, 48, 340-71). ^The general view is that 

 cyanides depress physiological processes in general, and the rate of 

 oxygen consumption in particular. The author has made a large 

 number of experiments on Planaria, which prove that its oxygen con- 

 sumption is decreased in the presence of potassium cyanide. The 

 amount of decrease ranges from 80-90 p.c. in 1/2000 mol. KNC ta 

 5-15 p.c. in 1/200,000 mol. solution. The decrease is independent of 

 muscular or ciliary activity. It is entirely reversible, the animals being 

 AvhoUy uninjured by the cyanide and returning to their normal rate of 

 consumption when the cyanide is washed out of them. Cyanide is a 

 general protoplasmic depressant. J. A. T. 



Effects of Cyanides on Planaria dorotocephala. — C. M. Child 

 {Amer. Journ. Physiol., 1919, 48, 372-95). Exposure to potassium 

 cyanide iu concentrations ranging from m/500 to wi/25,000, and for 

 periods from h to 61 1 hours, decreases the CO2 production in this 

 Planarian. If the exposure is not too long, gradual recovery in CO^ 

 production occurs, apparently with a supernormal stage near the end of 

 the recovery period. Susceptibility to lack of oxygen in Planaria shows 

 in general the same regional and individual differences as susceptibility 

 to cyanides and other toxic agents. KNC increases susceptibility to 

 lack of oxygen, i.e. an animal which has been in cyanide dies earlier 

 from lack of oxygen than a normal control animal. Since cyanides 

 decrease both oxygen consumption and CO., production in Planaria, the 

 increase by cyanide in susceptibility to lack of oxygen can mean only 

 that cyanide and lack of oxygen are to some extent additive in their 

 action on living protoplasm, i.e. their action must be in certain respects 

 identical or similar in character. J. A. T. 



Japanese Polyclads. — M. Yeri and T. Kaburaki (Journ. ColL 

 Sci. Univ. Tolcyo, 1918, 39, 1-54, 2 pis., 48 figs.). Very Httle has 

 hitherto been known of the Polyclad Turbellarian fauna of the Japanese 

 coasts. The authors' studies have revealed 26 species, of which 17 

 seem to be new. These belong to 14 genera, of which Neoplanocera 

 and Pseudostylochus are new. Numerous figures are given of the eye- 

 spots and the gonads. J. A. T. 



