Reciews — Royal Microscopical Socicti/'s Journal. 477 



highly creditable to the enthusiastic editor, Mr. Frank Crisp, one of 

 the Secretaries of the Society, and his talented and willino^ assistant- 

 editors, Messrs. Bennett, Bell, Ridle}-, and Mayall, also Fellows of 

 the Society. In the Parts before ns are ten original papers 

 on various matters in Microscopy. Professor Duncan's elaborate 

 Presidential Address, reviewing the aspects and value of the results 

 of high magnifying powers, is a most valuable addition to this 

 branch of the Society's study and research. There are also nine 

 original papers on natural history, treating of Mites. Spider-web, 

 a new boring Annelid, Si:)icules of Echinoidea, peculiar Sponge- 

 spieules, Diatomaceas, and Bacteria, Bacillus, etc., touching on the 

 medical question of their probable malignant influence in some 

 diseases. 



For the benefit of microscopists each part of the Journal (published 

 in February, April, June, August, October, and December) contains 

 the following useful, and indeed necessary, Tables : — I. Numerical 

 Aperture ; II. Conversion of British and Metric Measures ; III. 

 Corresponding Degrees in the Fahrenheit and Centigrade Scales ; 

 IV. Refractive Indices, Dispersive Powers, and Polarizing Angles ; 

 Y. Magnifying Powers. 



The Summary of current researches consists of abstracts of, or 

 extracts from the more important articles relating to the chosen 

 subjects (with references to originals), as contained in British and 

 Foreign Journals and Transactions, chiefly those added to the 

 Society's Library. The following notes bear evidence that these, 

 as well as the other contents of this valuable periodical, are of 

 intei'est to geologists. 



Those to whom the study of Cephalopoda is of special interest 

 will find a reference to the particulars about existing giant Squids, 

 such as the ArcMteutliis, at p. 586, vol. i. Some found dead on the 

 Grand Banks, bj'^ the Massachusetts fishermen, had bodies 15 feet 

 long, and 18 inches in diameter; some had arms 36 feet long; and 

 one was estimated to weigh lOOOlbs. 



P. Girod's researches on the ink-bag and ink of Cephalopods 

 (p. 876, vol. i.) are also of considerable interest, especially in view 

 of the frequent occurrence of such ink-bags in the fossil state. He 

 finds that the ink contains — 



Carbon 53-6 to 53-9 



Hydrogen 4 and a fraction 



Nitrogen 8-6 to 8-8 



Its constituents are — in 100 parts — 



Water 60 



Mineral substances 8'613 



Insoluble organic substances 30-o36 



Extractive matters 0"851 



The mineral substances include calcium, magnesium, sodium, 

 potassium, and iron ; and the acids include carbonic, sulphuric, and 

 hydrochloric, but not phosphoric acid. 



C. D. Walcott's investigations on the structure of Trilobites and 



