THE AMERICAN 
MONTHLY 
MICROSCOPICAL JOURNAL. 
Entered at the post-office as second-class matter. 
VOL, XXIl. DECEMBER, 1901, NO. 12. 
CONTENTS. 
The Ephippium of Bosmina, Scourfield 311-317 
On the Resolution of Amphipleura Pellucida with a Dry 
Lens and Axial Illumination. Merlin 317-323 _ 
Larval Water-mites on Aquatic Animals. Soar 323-324 
Viewing Diffraction Spectra. Reinberg._.. 324-325 
Sketch of J. D. Whelpley_........ Fae 325-328 
es eee ee re te ee 329-330 
Notes on Microscopy. M. I. Cross.—The Microscopical 
Examination of Metals; Multiplied Images in Diatoms.... 330-332 
Terms of Subrcription for 1902 332 
¢ 3 
’ The Ephippium of Bosmina. 
D. J. SCoOURFIELD. 
ILLUSTRATED. 
The production of winter or resting eggs in the genus 
Bosmina has been referred to by various writers on the 
Entomostraca, but I do not think that any description 
of the egg’s protective covering, which corresponds, of 
course, to the ephippium of the Daphnida, has hitherto 
been published. As this structure exhibits one feature at 
least which distinguishes it from the homologous produc- 
tions of all other forms of the Cladocera, it appears worth 
while to bring forward the present short paper on the 
subject. 
If we examine the recently thrown-off resting eggs of 
Bosmina longirostris enclosed in its protecting case (fig. 
