ON DEVELOPMENT OF ATYEPHIRA COMPRESSA. 391 
On the Development of a Freshwater Macru- 
rous Crustacean, Atyephira compressa, 
De Haan. 
By 
CliiyomatKii Ishikawa, 
Of the University of Tokio, Japan. 
With Plates XXV, XXVI, XXVII, XXVIII. 
The species on which the following observations were made, 
is very commonly found in freshwater streams and ponds in 
the vicinity of Tokio. Its specific determination has very 
kindly been made for me by Dr. Ed. J. Miers, of the British 
Museum, through the kind offices of Professor Whitman and 
Dr. Paul Mayer. Dr. Miers wrote a valuable paper on it, in 
the * Annals and Magazine of Natural History ’ for March, 
1882 (pages 193, 194). 
My investigations on the development of Atyephira com- 
pressa, De Haan, were begun in the spring of the year 
1881, under the direction of Professor Whitman, to whose 
valuable assistance and instruction I am deeply indebted. By 
the spring of the next year I had nearly completed the study 
of the development of the ovarian ovum, and on my gradua- 
tion in July of that year, wrote a thesis on this subject under 
the name of “ On the Ovarian Ovum of Atyephira com- 
pressa, De Haan.” In the spring of 1883 I extended my 
investigations to the development of the post-ovarian ovum, 
under the direction of Professor Mitsukuri, to whose constant 
VOL, XXV. — NEW SER. 
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