No. 1. — Contributions to the Morphology of the Turbellaria. — 

 I. On the Structure of Phagocata gracilis, Leicly. By W. M. 



WOODWORTH. 1 



In the fall of 1887, Mr. H E. Valentine of West Somerville, Mass., 

 brought to the Embryological Laboratory of Harvard College some 

 planarians, with the suggestion that they might be infested with para- 

 sites. The planarian proved to be the interesting Phagocata gracilis of 

 Leidy, and the supposed parasites were the pharynges of the complicated 

 digestive apparatus. At the suggestion of my instructor, Dr. E. L. 

 Murk, I undertook, the study of this curious Triclad. 



The animal, which was afterwards named by Leidy Phagocata gracilis, 

 was first described by S. S. Haldeman ('40, p. 3) in 1840, under the 

 name of Planaria gracilis : " Body oblong, suddenly tapering to a point 

 posteriorly : sides nearly parallel ; head square in front, with a project- 

 ing appendage on each side : neck narrowed ; eyes (two) sitrated on 

 each side of the narrower part ; these are oblong and white, with a 

 black dot at their internal side : ventral opening less than one third 

 the entire length from the posterior extremity, and from this open- 

 ing an intestine is sometimes protruded. General color fuliginous, 

 veined with black. Length, | hi., breadth, ^. Hab. springs in Eastern 

 Pennsylvania." 



In 1848, Leidy published a further description of the species, giving to 

 it the name of Phagocata ('48, p. 248), because, as he says, " I detected 

 such a remarkable peculiarity in the digestive apparatus as led me to 

 investigate its anatomy in detail, and to form for it a separate sub-genus, 

 characterized as follows : — 



"Phagocata, oblonga, plano-convexa, nuda, contractors, mucosa, an- 

 tica auricularia. Aperturse dure, ventrales, ad os et ad generationem 

 pertinens. Proboscides multaj. 



1 Contributions from the Zoological Laboratory of the Museum of Comparative 

 Zoology, under tlie direction of E. L. Mark, No. XXIV. 



No XXIII. of these Contributions appeared in the Proceedings of the American 

 Academy of Arts and Sciences, Vol. XXV., under the title, "Preliminary Notice 

 on Budding in Bryozoa." By C. B. Davenport. 



vol. xxi. — no. 1. 1 



