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 Uebersetzungsrecht vorbehalten. 



A Contribution to the Life-history and Anatomy of the 

 Appendiculate Distomes. 



By 

 H. S. Pratt, Ph. D., Haverford College, Penn. 



With Plates 26—27. 



Contents. 



Introduction. 



Form and size of the worm described. 



The integument, with a consideration of the nature and morphological 



significance of the Trematode-cuticula. 

 The musculature. 

 The parenchyma, with a consideration of the nature and function of 



the submuscular cell-layer. 

 The excretory system. 

 The digestive system. 

 The nervous system. 

 The sexual organs. 

 General considerations : 



On the life-history of appendiculate Distomes. 



On the morphological significance of the appendix. 

 Methods. 



Literature reierred to. 

 Explanation of the figures. 



Introduction. 



The appendiculate Distonie which is the subject of this paper 

 was found in the tow collected in Long Island Sound at Cold 

 Spring Harbor in the summer of 1896. It is a minute worm, 

 less than a millimetre in length, cylindrical in shape, with rather 

 large oral and ventral suckers, and was first observed wriggling actively 



