40 Proceedings of the Royal Society of Victoria. 



is a large quantity of tissue formed of small spindle-cells. 

 The oval apertures between the papilte lead to ciliated pits, 

 the appearance ])resented by which is shown in Figs. 11, 12, 

 and 13, Plate XV. In longitudinal and horizontal sections, 

 the appearance presented in Fig. 1 3 is seen. The light bands, 

 which appear to pass to the V)ottoms of the ciliated yjits, are 

 continuous with the vascular* network of the head. Whether 

 they represent tubes in communication here with the 

 exterior, 1 cannot say. They may convey nerves to the sacs. 

 From the manner in which the animal uses the front of its 

 head, their can be little doubt that the papillary line 

 discharges some special sense-function ; but it is possible 

 that this function is discharged by the papillae, whilst the 

 ciliated pits, with their communicating vascular stems act as 

 excretory organs. The papillary line, with its pits, was 

 found in all the species of 5<!'^>«/ift»i examined. The ciliated 

 sacs of Nemertines came at once, of course, into one's mind 

 in conection with these curious structures. Careful exami- 

 nation may perhaps give evidence of the existence of 

 similar ciliated sacs in Geoplava and other Planarians. 

 Nothing of the kind was found in HhyncJtodeinus." 



Although Professor Moseley subsequently studied and 

 described-f- species of Geoplana from New South Wales and 

 elsewhere, he failed to discover tlie presence in them of 

 ciliated pits. Von Kennel, also, makes no mention of them 

 in the German land Planarians belonging to the genera 

 Mhyachochmus and Geodesmus, which were carefully inves- 

 tigated by him,;]: nor have they hitherto been discovered by 

 any of the Australian zoologists who have more recently 

 paid attention to the group. In my memoir on "The 

 Anatomy of an Australian Land Planarian," published in the 

 Transactions of this Society for 1889, no mention is made of 

 an}' such organs, nor did I at that time suspect their 

 existence, so that, so far, the memoir is incomplete, and I am 

 glad ol' the present opportunity of making up the deficiency. 



The object of the present communication, therefore, is to 

 record the occurrence and describe the structure and 

 arrai]gement of ciliated pits in Australian land Planarians 

 belonging to the genei'a Geoplana and Rhynchodemus. It 



* This is now known to be a nervous, and not a vascular, structure. — A. D. 



t "Notes on the Structure of Several Forms of Land Planarians, &c." 

 Quarterly Journal of Micro)>copical Science, Vol. XVII (N.S.), p. 273. 



+ "Die in Deutschland p;efundeuen Land))lanarien, etc." Arbeiten des 

 Zool.— Zoot. Institut in Wiirzburg, Band V, Heft 2. 



