970 



SCIENCE. 



[N. S. Vol. XXIII. No. 600. 



A. Daly; "The 'Method of Effective Aver- 

 ages' for Dealing with the Equations of 

 Chemical Kinetics,' by R. E. DeLury; 'In- 

 duction of the Reaction between Arsenious 

 Acid and Chromic Acid by Hydrogen 

 Iodide,' by R. E. DeLury; 'The Formation 

 of Acetic Acid by the Action of Chromic 

 Acid on Alcohol,' by C. F. Marshall; 'The 

 Mechanics of the Reaction between Iodine 

 and Starch,' R. B. Stewart. 



And the papers of Section III. close 

 with the following: 



'Isomorphism as Illustrated by Certain 

 Varieties of Magnetite,' by Dr. B. J. Har- 

 rington. 



'An Investigation on the Value of the 

 Indentation Test for Steel Rails, ' by H. K. 

 Dutcher, and introduced by Professor 

 Henry T. Bovey. 



SECTION IV. GEOLOGICAL AND BIOIjOGICAL 

 SCIENCES. 



Not less than twenty-nine papers or con- 

 tributions were recorded on the work of 

 this section last week. They include the 

 following : 



'Illustrations of the Fossil Fishes of the 

 Devonian Rocks of Canada, Part III.,' by 

 Dr. J. F. Whiteaves. 



This paper is mainly a revision of the 

 author's previous well-known papei's on the 

 Upper and Lower Devonian fishes of Scau- 

 mence Bay, Quebec, and of Campbellton, 

 New Brunswick. 



'The Form and Structure of Lamp- 

 organs in Certain Fishes,' by Professor 

 Edward E. Prince. 



The author describes the minute micro- 

 scopic structure of certain phosphorescents, 

 notably those of Mmirolimts, and is unable 

 to support von Lendenf eld's view that 

 clavate cells are an essential feature in 

 them. The emission of light observed by 

 the author, and the lamp-like arrangement 

 of the parts of these organs (including 

 phosphorescent adenoid material, a silvery 



reflector, and a clear bull's-eye lens), all 

 indicate the purpose of these curious struc- 

 tures in the deep-sea fishes referred to in 

 the paper. 



'New Points in the Structure and De- 

 velopment of the Pharyngeal Teeth in 

 Fishes,' by Professor Edward B. Prince. 



The author finds, from the study of sec- 

 tions of the pharyngeal teeth of fishes, in 

 early stages of development, that their 

 structure is more complex than is usually 

 admitted. Goodsir, Tomes and other 

 eminent authorities have described involu- 

 tions of the buccal epithelium to form the 

 external and internal enamel organ, but 

 Balfour's surmise is correct that the whole 

 dental sac is endodermic, at any rate in 

 pharyngeal teeth in fishes. In each sac 

 may be distinguished: a delicate external 

 stratified layer or sac-well; a layer of 

 cubical epithelial cells (the external enamel 

 organ) which are infolded to form the in- 

 ternal enamel organ; and a papilla or cen- 

 tral dental pulp. A cone of clear dentine, 

 which is readily stained with carmine, is 

 developed from the papilla ; while the large 

 palisade epithelium forming the inner 

 enamel organ secretes the clear bright mat- 

 ter, which is determined to be enamel. Dr. 

 J. Beard found, even in the teeth of low 

 fishes, like Myxine and Bdellostoma, all 

 the features referred to, recalling the de- 

 tails given by 0. Hertwig, in Amphibian 

 teeth. The distinctness of the inner den- 

 tine and the outer or enamel layer is ■ so 

 marked that Owen's view can not be ac- 

 cepted that all dental tissues in fishes are 

 modifications of dentine only, and Hert- 

 wig 's statement that enamel is a secretion, 

 and not as Tomes held, transformed epi- 

 thelium cells, is confirmed. 



'On Amyzon hrevipimie Cope, from the 

 Amyzin Beds of the Southern Interior of 

 British Columbia,' by Lawrence M. Lambe. 



In this paper a description of Amyzon 

 hrevipinne Cope is given, based on a sec- 



