1913J R. H. Whitehouse : Freshwater Planaria. 



319 



developing egg-cells in different stages of development. However, 

 serial sections reveal no trace of oviducts or uterus, which acces- 

 sories may be later developments. This condition of things seems 

 to support the suggestion that this and some other species are 

 sexual individuals at one time of the year and asexual at another. 

 The animals examined were collected in January. There is of 

 course the possibility that here we have a dioecious species of 

 Planaria only the female of which has been discovered. 



Planaria kcmpi, n. sp. 



(Plate xxii, fig. 4.) 



Only a single specimen of this species was obtained ; it was 

 9'5 mm. in length, and 2 mm. across the widest part of the body 

 at the root of the pharynx. 



Fig. I, — Genital apparatus of P. kcmpi (semi-diagrammatic and drawn by 

 reconstruction from serial sections, g.a. genital atrium; g.o. genital opening ; 

 m. mouth; m g. muscular mucous glands; od. oviduct; p. penis; p.s. penis sheath; 

 ut. "uterus" or shell gland: ut. d. "uterine duct"; v.d. vas deferens; v.s. 

 vesicula seminalis. 



The head merges gradually into the trunk and thus no neck 

 is dift'erentiated. The hind end of the body tapers very little less 

 than the head. The two eyes are fairly closely approximated, the 

 distance between them being about half the distance from the eye 

 to the margin of the head ; each eye is surrounded by a non-pig- 

 mented area. The colour of the dorsal surface is a medium brown 

 of even distribution. The ventral surface is much paler in colour 

 than the dorsal side, and possesses two apertures, the mouth 3'75 

 mm., and the genital aperture 2"75 mm. from the posterior end. 



The pharynx occupies a position in the middle of the body, 

 and is about 2*5 mm. in length and less than i mm. in width. The 

 rest of the gut conforms to the usual plan, and is much less 

 branched than in the previous species; neither does it extend 

 so far forward. 



