On the reproductive system of Planaria simplissima, 455 



globules of different degrees of refraction (PI. 32, Figs. 9 and 11 v). 

 These vacuoles occur in great numbers at the peripheral parts of the 

 cytoplasm in every large ovum. As they were found in material killed 

 in plain corrosive sublimate there would seem to be nothing in the 

 reagent used to produce such an effect. My preparations in which 

 these are shown were studied by the late Dr. Arnold Graf who 

 believed them to be vacuoles and to indicate some important activity 

 of the growing ovum. He was not of the opinion, however, that the 

 masses within them represented nuclei in process of absorption after 

 the manner described by Brooks ('93, p. 223) in the maturation 

 of the egg of Salpa, which is the idea I am inclined to adopt 

 from the way the nuclei of the supporting substance surround the 

 ova. In this connection it is of interest to note that small clear 

 spaces of exactly similar appearance are often found in the cytoplasm 

 of the large yolk cells during the stages of the vitellaria examined 

 (PL 32, Fig. 9 yc). 



The oviducts (PI. 31, Figs. 1 and 8 od) are delicate tubules of 

 a connective tissue substance similar to that surrounding the ova and 

 continuous with it where the oviduct leaves the ovary at its upper 

 and outer portion (PI. 32, Fig. 9). Passing backward just above the 

 longitudinal nerve-trunks they begin to converge slightly, opposite the 

 free end of the pharynx, and on nearing the mid-line behind the 

 genital atrium turn sharply to run forward mounting dorsally at the 

 same time and immediately unite into a short common oviduct (cod). 

 This can be seen best in the lateral view of the organs represented 

 in PI. 31, Fig. 8. The common oviduct strikes the vagina (va) from 

 behind at a right angle, opposite to the entrance of the uterus (ut), 

 forming with the latter the arms of a "T" of which the vagina is the 

 upright. The vagina passes downward and forward to enter the 

 posterior and dorsal part of the atrial chamber just above the canal- 

 like pore to the outside. The continuity of the oviduct has been 

 demonstrated by the method used for the vas deferens. There is a well 

 defined lumen along the whole length, but the outer boundary of its 

 wall is less distinct. This oviduct wall was a riddle to me from the 

 first and was only solved through the structure of the young yolk- 

 glands. There is between the vitellaria, oviduct and ovary such an 

 intimate relation that they must be described as a whole, but in the 

 vitellaria the structure is found reduced to its lowest terms and when 

 they are understood the other two are easily interpreted. 



The earliest condition of the yolk glands observed were short 



Zool. Jahrb. XUI. Abth. f. Morph. 3Q 



