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 (Jebersetzunysrecht vorbehalten. 



On the Reproductive System of Planaria simplissima, 



a new species. 



By 

 Winterton C. Curtis, Baltiinore. 



With Plates 31 and 32. 



The Planarian which forms the subject of this study was found 

 in a mountain stream (West Brook) near Williamstown Mass. Its 

 external features do not correspond with any descriptions which I have 

 found of American or other forms, nor is the internal anatomy like 

 that described elsewhere. Dr. Wm. Mc M. Woodworth of Harvard 

 University, after examining the living specimens and my drawings of 

 the internal anatomy, assures me that it is unlike any form with which 

 he is acquainted. I shall therefore describe it as a new species of 

 the genus Planaria. 



Planaria simplissima n. sp. Color uniform slate to slate black, 

 no mottling. Pigment wanting over the eyes which appear as two 

 crescentic areas set facing outward at an angle of about 45 ° to the 

 axis, and are of a light gray color contrasting sharply with the darker 

 surface. Anterior end blunt. No lateral cephalic appendages, but slight 

 median anterior projection. Width at head almost as great as at widest 

 part, increasing uniformly from head backwards until greatest width is 

 reached about the middle, thence tapering to a pointed posterior end. 

 Specimens found as long as 8 mm, when fully extended. Ratio of length 

 to width 3:1. While the distance between the dorsal and ventral sur- 

 faces in the living specimens is hard to estimate the worm is relatively 

 thick and less flattened than such a form as Planaria maculata. Mouth 

 V.-j the total length from the posterior end. With the exception of the 



