ciliated Fits in Australian Land Planarians. 41 



seems .strange that these have not been discovered before^ 

 but they are of extremely minute size, invisible with a 

 pocket lens, while even under a low power of the microscope 

 their tru*^ nature is ditiicult to make out ; when, however,, 

 they are examined undei certain favourable conditions, 

 which will be described presentl} , they are very clearly 

 \isible indeed. 



The followincr is a list of the s})ecies in wliich I have found 

 them -.—Geo plana spencevi, G. alha, G. ventvolineata,. 

 G. muiida, G. ventro punctata.. G. quinquelineata, G. hoggii, 

 G. adw, G. Goeridea (blue-tipped variety), G. dendyi, 

 G. quad rang idata var. ivellingtoni, G. sugdeni, G. fletclieri,. 

 G. kovntti var. obsoleta, G. wediolineafa, G. on'mahoni, and 

 Mhynchodemuti ,s imidans. 



Of these species I have examined the ciliated pits in the 

 living state only in Genplana ventrolineata, G. alba and 

 G. cceralea (blue-tipped variety). In the other species I have 

 clearly recognised them in spirit-presei'ved specimens. In 

 short, I believe that the ciliated pits occui- in all species of 

 Geoplana and Rhynchod.emus. 



1 tirst noticed the pits in examining some spirit-preserved 

 specimens of Geoplana ventrolineata as opaque objects under 

 a low power of the microscope. I found on the ventral surface, 

 at each side of the anterior extremity, a light longitudinal 

 line, devoid of pigment, slightly curved as shown in Fig. 6^ 

 and apparently slightly raised as a ridge, but this raised effect 

 was doubtless exaggerated by the dispo,sition of the pigment, 

 for hardly any ridge is vi.sible in transverse sections (Fig. 7). 

 This line lies beneath the line of eyes, and obviously 

 corresponds to the margin of the horse-shoe-shaped anteii(.)r 

 extremity in the living animal. Along the inner mai'gin of 

 the light line on each side was visible a single row of very 

 minute dark specks, which proved on careful examination 

 to be minute punctuations like those made by tiie point of a 

 very tine needle. These punctuations are arranged with 

 great regularity, and extend throughout the entire length'of 

 the light line, disapi)earing as the latter dies out posteiiorly. 

 1 could not determine whether or not the punctuations were 

 continued all round the anterior mai-gin ; the\- are only 

 cleai-ly visible in a good light, and it is ]M)ssible that I may 

 have overlooked them in front. 



Having satisfied myself as to the presence of the line of 

 pits in G. ventrolineata I went through my collection and 

 examined all the other species I had under similar conditions. 



