i CONTENTS. 



No. 6. May, 1898. 



PAGES 



I. W. S. NlCKERSON. 



On the Occurrence of Distomnin Ovocau- 



datum Vulpian in American Frogs . . 261-264 



II. FRANK R. LILLIE. 



Ccntrosoinc and Sphere in tJie Egg of Unio 265-274 



III. HOWARD AYERS. 



On tJie Membrana Basilaris, tJic Membrana 

 Tectoria, and tJie Nerve Endings in tJic 

 Human Ear 275-278 



IV. ROBERT H. WOLCOTT. 



New American Species of the Genus Atax 



(Fab.} Bruz 279-285 



V. T. H. MORGAN. 



Regeneration and Liability to Injury . . 287-300 



VI. HENRY LESLIE OSBORN. 



Observations on the Parasitism of Anodonta 

 Plana Lea by a Distomid Trcmatodc, at 

 Cliautauqua, New York 301-310 



VII. WILLIAM PATTEN. 



The Structure and Origin of the Excretory 



Organs of L imu Ins 3 II ~3 I 3 



