1906.1 NATURAL SCIENCES OF PHILADELPHIA. 



PLANARIA MOEGANI n. sp 



BY N. M. STEVENS AND A. M. BORING. 



Size. — Length 10-12 mm., width in the region of the pharynx 1.6 

 mm., at the level of the eyes 1 mm. 



Form. — Head wedge-shaped, no auricular appendages, posterior 

 end obtuse, thickness slight compared with Planaria maculata or P. 

 simplicissima (Plate I, figs. 1 and 2). 



Color. — ^White and translucent; digestive tract often colored green, 

 yellow, brown, or red by food recently ingested. 



Eyes. — ^Two, crescent-shaped, situated far back and near together 

 (PI. I, figs. 1-4). 



Nervous Systejn. — Cephalic ganglia large and distinct, connected by 

 a broad commissure, lateral nerve cords as in P. maculata, two promi- 

 nent nerves extending forward from below the eyes (Plate I, fig. 4). 



Pharynx. — Single, much elongated, centrally located in forms with 

 functional sexual organs, posterior to the center in forms which are 

 reproducing asexually (Plate I, figs. 1 and 2). Digestive tract as in 

 the typical triclads with little anastomosis of branches (fig. 3). 



Reproductive Organs. — Ovaries two, situated ventrall}^ between the 

 anterior axial division of the gut and its first lateral branches, some- 

 times lobed, and often extending nearly to the dorsal epidermis 

 (Plate I, fig. 4). Oviducts following a spiral course dorsal and slightly 

 lateral to the nerve cords, back to the region of the atrial organs, 

 where they converge and unite into a short common oviduct which 

 enters the atrium dorsal to the opening of the uterus stalk, instead of 

 entering a vagina as in P. maculata (Cm-tis, '02). Spermatozoa are 

 often found massed at the anterior end of the oviducts. Yolk glands 

 lie between all of the main branches of the gut dorsal to the testes. 

 Testes many, irregular in form and variable in size, scattered between 

 the branches of the gut, for the most part ventral and median to the 

 nerve cords, and extending from the region of the ovaries to the 

 posterior end of the pharynx (fewer and larger than in P. maculata). 

 Distinct seminal vesicles extending posteriorly from the last pair of 

 testes (y.s., Plate I, figs. 5 and 6). Vasa deferentia broad, short and 



