January 28, 1916] 



SCIENCE 



143 



alone cause a strong increase in the positiveness 

 of the rheotactie reaction of the isopod, Asellus 

 communis Say. Sodium has a similar but less 

 pronounced efEeet. The efficiency of the chlorine 

 salts in causing this change is: 



C's < Li < Na < Eb < K, 



or, arranging in order of their chemical activity: 



Li < Na < K > Bb > Cs. 



The anions also affect the rheotactie reaction. 

 In a series of potassium salts KCl gives the great- 

 est increase in positiveness. The favorableness of 

 the anions tested is: 



Br, I, N03 < CH3C00, < CIO3 < SCN < Cl, 



with chlorine much more favorable than its near- 

 est competitor. The relative toxicity of neither 

 the anions nor kations runs parallel with their 

 relative effect on rheotaxis. 



Any ion in the concentrations (usually 

 jVr/.5 — N/10) used in these experiments will 

 cause a decrease in the positive rheotactie reac- 

 tion if allowed to act for sufficient time. Calcium 

 almost always causes this depression without a 

 preliminary increase. Strontium and barium act 

 similarly, but magnesium often stimulates before 

 depressing. 



By alternating an isopod between N/IO solu- 

 tions of KCl and CaClj its rheotactie reaction has 

 been alternately increased and decreased as many 

 as seven times in the six hours before the animal 

 succumbed to the treatment. 



Negative isopods treated with KCl until strongly 

 positive have their resistance to N/iOO NaCN de- 

 creased, which indicates that their rate of meta- 

 bolic activity has increased. CaCL has exactly the 

 opposite effect. These results support earlier 

 work on the relation of rheotaxis and metabolism 

 in Asellus. 

 Glacier OUgochmta from Mt. Bainier (illustrated 



with lantern) : Paul S. Welch, Kansas State 



Agricultural College. 



MesencJiytrwus solifugus (Emery, '98; Moor3, 

 '99; Eisen, '05) and Mesenchytroeus niveus 

 (Moore, '99), found on certain Alaskan glaciers, 

 are apparently the only recorded Oligoehasta which 

 normally inhabit snow and iee. Six collections, 

 January 7 to June 17, 1915, from the snowfields 

 and glaciers of Mt. Eainier, Washington, contain 

 an undescribed enehytrEeid (MesencJiytrceus gelicus 

 n. sp.) which occurs abundantly in that very un- 

 usual habitat. Among the remarkable structural 

 characters of this worm, the extent and complexity 



of the reproductive organs are perhaps most note- 

 worthy. A pair of very large spermatheese extends 

 from IV./V. to XL, almost completely filling the 

 coelom, and containing surprising quantities of 

 spermatozoa. A pair of well-developed sperm 

 sacs, extending from XI./XII. to XXXV. and 

 containing large masses of developing spermatozoa, 

 are surrounded by a large ovisac which extends 

 from XII./XIII. to XXXV. and contains in addi- 

 tion large quantities of developing ova. The 

 penial bulb is very complex in organization. The 

 specimens are very dark in color, due to the large 

 amount of pigment in the hypodermis. Certain 

 internal organs, especially the spermatheeaB, 

 chloragog cells and lymphocytes also contain pig- 

 ment granules. The collections also contain speci- 

 mens of M. solifugus Emery, a form which occurs 

 in abundance on the permanent snow and ice fields 

 of Mt. Eainier. Evidence points to certain snow 

 algae as one of the chief sources of food for both 

 of these worms. 



The Eeaction of Fishes to Stimuli not Encountered 

 in their Normal Environments: V. E. Shelfobd, 

 Illinois State Laboratory of Natural History. 

 Wastes from the manufacture of illuminating 

 gas are commonly thrown into streams and are 

 probably more generally fatal to fishes than any 

 other industrial wastes. In course of the investi- 

 gation of the effects of products of the destruc- 

 tive distillation of coal upon fishes about twenty- 

 five compounds have been studied. Nearly all are 

 rapidly fatal when present in minute quantities. 

 The reactions of fishes to these ingredients have 

 been tested and the fishes tested are positive to 

 fifteen of the twenty-five compounds, indefinite or 

 indifferent to seven and negative to only two or 

 three. Thus the reactions of the fishes are of 

 such a nature as to destroy rather than to preserve 

 them. 



COMPARATIVE AND GENERAL PHYSIOLOGY 



The Eelation Between Wave-length and Stimula- 

 tion in the Lower Organisms : S. 0. Mast, Johns 

 Hopkins University. 



The relative stimulating effect of different re- 

 gions of a spectrum having a known distribution 

 of energy was ascertained for the following fif- 

 teen species: Chlamydomonas, Trachelomonas and 

 Fliacus, each one species; Fandorina, Eudorina, 

 Gonium and Spondylomorum, each one species; 

 earthworms, Arenicola (larvae) and blowfly 

 (larvae) each one species. 

 The results obtained are briefly stated below 



