THE DEVELOPMENT OF THE TEMNOCEPHALEvE. 415 
The Development of the Temnocephaleee. 
Part I. 
By 
Professor W. A. IfasAvell, Ifl.A., D.Sc., F.R.S. 
With Plates 23—25. 
I. Introduction. 
Though several additions of importance^ have been made 
to the literature concerned with Tern noceph ala and its 
allies since 1893, when I published an account of the group 
under the title “ A Monograph of the Temnoceplialese ” (8), 
no attempt has been made hitherto to deal with the embryo- 
logy of any of its members. In view of the interest which 
attaches to them on account of their isolated character and 
problematical relationships with other sections of Platodes, 
it is very desirable that something should be done towards 
filling this hiatus iu our knowledge. 
What follows is by no means a complete or exhaustive 
account of this subject. It is concerned mainly with the 
developmental history of a single form — viz. Temno- 
cephala fasciata — one of the most widely distributed 
of the Australian representatives of the group : and in this 
■ The most extensive and important of these is that of Wacke (16), 
published in 1900. When writing this the author had, apparently, not 
liad tlie opportunity of consulting my “ Monograph," and all his refer- 
ences, critical and otherwise, concern themselves with a short paper 
which I publislied in 1888 in the ‘ Quarterly Journal of Microscopical 
Science.’ Hence there is a good deal that goes somewhat wide of the 
mark. 
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