Art. VIII. — 0)1 the Presence of Ciliated Pits in 

 Audralian Land Planarians. 



(With Plate V.) 



By Arthur Dendy, D.Sc, F.L.S. 



[Read September 10, 1891.] 



In his well known memoir, " On the Anatomy and 

 Histology of the Land Planarians of Ceylon," * Professor 

 Moseley describes the presence of ciliated pits on the anterior 

 margin of the head of Bipalimn. As his remarks on these pits 

 are short, and at the same time of great interest. I may jierhaps 

 be allowed to quote them in full: — "In describing the habits 

 of Bipaliuiii, I described the manner in which the animal 

 throws out tentacular-like projections from the anterior 

 margin of its semi-lunar head when in motion, and evidently 

 uses these temporary tentacles as sense organs. In reading 

 M. Humbert's interesting account of Blpalium, I found that 

 he had observed this habit of the animal as well as I, and 

 had been led by his observation to seek for sense-organs or 

 tentacular structures on the margin of the head. He was 

 not successful in rinding any ; but on very carefid examina- 

 tion of well-hardened specimens I was more fortunate, and 

 discovered a narrow band extending along the whole 

 anterior margin of the head, entirely free from pigment, and 

 occupied by a row of cylindrical rounded papillae placed 

 vertically side by side, and with small oval openings 

 between their superior extremities (Plate XIII, Fig. J 6). 

 This row of papillae is in the upper part of the lower fifth 

 of the margin of the head, so that it lies close to the ground 

 when the animal's head is lowered. The papillfe are covered 

 with short cilia, but I could find no special structure in them, 

 except tiiat in their region, and that of the ciliated pits, there 



• Philo.sophical Transactions of the Royal Society, 1874. 



