131 
THE OVA OF SCHISTOSOMA JAPONICUM 
AND THE ABSENCE OF SPINES. 
By PAUL G. WOOLLEY, 
AND OTTO Y. HUFFMAN, M.D. 
(From the Laboratories of the Cmcinnati Hospital, 
Cincinnati, 0., U.S.A.) 
The observations recently set forth by Dr Leiper^ and by Dr Sambon 
in a discussion b have led us to re-examine the ova of S. japonicum in 
the material which we have at hand. This material was described 
previously by one of us^ together with a report of some comparative 
measurements of the ova of this species of trematode furnished by 
Dr Shiga. 
We have now re-examined carefully several hundred ova in stained 
sections of tissues and a great number of others which we have teased 
free from unstained tissues which have been well preserved in Kaiser- 
ling’s solution. In no instance did we find the least appearance of a 
blunt protuberance or spine on the outer envelope of the egg. In one 
or two instances the embryo itself caused a slight protuberance about 
the size of the spine represented in Dr Leiper’s microphotograph, but 
without any of the other characteristic points reported by Dr Leiper— 
for instance the thickening of the envelope about the protuberance. 
When examining the ova of S. mansoni we have never experienced 
any difficulty in recognizing the lateral spines, and if the blunt lateral 
1 Leiper, E. T. (iii. 1911). Note on the presence of a lateral spine in the eggs of 
Schistosomum japonicum. Trans. Soc. Trap. Med. and Hyg. iv. p. 133. (Discussion, p. 135.) 
^ Woolley, P. G. (i. 1906). The occurrence of Schistosoma japonicxun vel cattoi in the 
Philippine Islands. PhiUppine Jourh. Science, i. p. 83. 
Parasitology iv 
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