16 THE AMERICAN MONTHLY [Jan 



avenue of escape. The bits were not swallowed but 

 dropped in the jar and are now in evidence. The mandi- 

 bles must be harder than the metal in order to cut it. 



This beetle is called Zopherus Americanus. It has not 

 been known to cut iron or steel. 



Live Specimens. — Amoeba, Arcella, Actinosphaerium, 

 Desmids, Diatoms, Floscularia, Hydra, Melicerta, Spiro- 

 gyra, Stentor, Vol vox, Vorticella and many others can be 

 got at 25 cents per tube postpaid from Thomas Bolton, 25 

 Balsall Heath, Birmingham, England. 



RECENT PUBLICATIONS. 



Petrology for Students. — This is the title of Alfred Har- 

 ker's little guide to the study of rocks in thin sections. A 

 second edition has recently come from the Cambridge Uni- 

 versity Press. Increased attention has been given to the 

 American igneous rocks. 



Mammals, Birds, Fishes. — New book by Dr. R. W. 

 Shufeldt, 400 pages, 130 nice illustrations, popular but 

 scientific. $3.50. Studer Bros., New York City. 



FOR SALE— DIATOMACEARUM SPECIES TYTICM 



Hamilton L. Smith. 



Seven hundred slides of typical species of Diatoms, in 

 28 rack boxes, book form, the boxes 6 5-8 x 4 1-8 x 1 3-8 

 iuches. Printed labels on each slide, and names on bot- 

 tom of boxes inside, under each slide, and a list of the 

 slides on a card in each box. Grood as new. Cost $140 

 will sell for |50. Also 



Monthly Microscopical Journal, containing Trans. Royal 

 Micros. Society, 1869-'7*7, 9 years, bound, 18 volumes; 

 Jour. Royal Micros. Society, 1878-'94, 17 years, bound, 

 28 volumes. In all 46 vols, in good order. Price $46. 

 Addrefls— -M. J. care of this Journal. 



