VOL. XL, NO. 470 



FEBEUAEY, 1906 



THE 



AMERICAN 

 NATURALIST 



A MONTHLY JOUENAL 

 DEVOTED TO THE XATTJEAL SCIENCES 

 m THEIR WIDEST SENSE 



CONTENTS 



I. The Unity of the Gnathostome Type ..... DB. H. AYER8 7S 

 n. Old Age in Brachiopoda - a Preliminary Study . . . DE, H- W. SHIMEE 95 

 m. The Habiti of Necturus maculosus PEOFESSOE A. C. EYCLESHYMEE 128 



IV. Notes and Literature : Zoology, Keilogg's American Ini^ects, Kingsley's Ele- 13T 



of Iceland, Holder's Half Hours with the Lower Animals ; Notes, Addi- 

 tional Records for New England Crustacea (J. A. Cushman) ; Botany, Smith's 143 

 Bacteria in Relation to Plant Diseases, Farlow's Index of North American 

 Fungi, Osterhout's Experiments with Plants, Sargent's Manual, Notes, 

 The Journals; <?eo%/, Notes 15i 



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