1912.] 



NATURAL SCIENCES OF PHILADELPHIA. 



487 



as far as a point midway between the sucker and the posterior end 

 of the gut and laterally half-way to the margin of the body. Not 

 far behind the pharyngeal pocket the meshes of the vasa deferentia 

 converge (PI. XV, fig. 25) to form a pair of ducts which pass abruptly 

 inward to enter the seminal vesicle from the rear. This last organ 

 is large, oval, and the ejaculatory duct leaving its anterior border 

 passes quickly to the base of the penis, communicating with the 

 exterior immediately below the posterior margin of the pharyngeal 

 sheath. 



The ovaries (PI. XVI, fig. 33) are dorsal, but the ducts connecting 

 them are invisible in total mounts. The uteri, on the other hand, 

 are clearly defined and fuse behind the posterior end of the gut, 

 forming a short median canal. From this point they extend ante- 

 riorly on either side of the main gut for nearly its entire length and 

 open to the exterior immediately below the posterior end of the 

 seminal vesicle. Numerous radiating ductules (PI. XV, fig. 25) 

 from the shell gland centre in the neighborhood of the vagina. 



Bibliography. 



Heath, H.: The Anatomy of Epibdella squamula, Proc. Cal. Acad. Nat. Sci., 



Vol. 3, 1902. 



A New Turbellarian from Hawaii, Proc. Acad. Nat. Sci. Philadelphia, 1907. 



Laidlaw, F. F.: On the Marine Fauna of Zanzibar and British East Africa, 



Proc. Zool. Soc. London, Vol. 2, 1903. 

 Lang, A.: Fauna und Flora des Golfes von Neapel, Vol. II, Die Polycladen. 

 Plehn, M.: Neue Polycladen, Jena. Zeit. f. Naturw., Bd. 30, 1895.~ 



Drei neue Polycladen, Ibid., Bd. 31, 1898. 



Stimpson, W.: Prodromus descriptionis anamalium evertebratorum, etc., Proc. 



Acad. Nat. Sci. Philadelphia, 1S57. 



Explanation of Abbreviations used in Figures. 



ab anterior intestinal branch. 



ae marginal eyes. 



af ant rum-f emininum. 



ag accessory gland. 



ai intestinal anastomoses. 



am antrum-masculinum. 



b brain. 



be bursa copulatrix. 



be brain (or cerebral) eyes. 



dp dorsal pits. 



ed ejaculatory duct. 



gg granular-gland. 



gs gland-like structures. 



ib lateral intestinal branches. 



im inner mouth. 



m mouth. 



mg mid-gut. 



nt nuchal tentacles. 



ova. 

 32 



od oviduct. 



os ovaries. 



p pharynx. 



pp pharyngeal pocket. 



ps penis. 



pss penis sheath. 



pt dorsal pits. 



sa pouch of antrum-masculinum. 



sc shell chamber. 



sg shell glands. 



sv seminal vesicle. 



t marginal tentacles. 



te nuchal tentaclfe eyes. 



ts testes. 



u uterus. 



ug uterus-gland. 



v vagina. 



vd vas deferens. 



vs ventral sucking disk 



