110 Froceedinrjs of the Royal Society of Victoria. 



lies in close proximity to the oesophagiis in the adult animal, 

 and this position, taken together with its histological struc- 

 ture, leaves little doubt in my mind as to its homology with 

 the portion of the latei-al organ derived from the oesophagus 

 in other Nemertines. It receives at its anterior end, as 

 already stated and as sliown in Fig. 4*, a special nerve from 

 the dorsal lobe of the brain, or, to speak more accurately, a 

 branch of the «ame nerve which supplies the ganglion of the 

 lateral organ. 



We must return nmv to the consideiation of the ciliated 

 duct, or cephalic pit, which we left just as it was entering 

 the ganglion of the lateral organ. At this point it divides 

 into two branches (Fig. 4). One of these branches penetrates 

 through the middle of the ganglion of the lateral organ and 

 thence enters the substance of the oesophageal organ, where 

 it disappears ; its course is represented by the dotted red line 

 in Fig. -!<. 



The other branch of the duct turns outwards and, passing 

 in front of the ganglion of the lateral organ, dilates into a 

 relatively large, hollow, laterally compressed vesicle (Figs. 

 2, 3, 4, .s'ac). The wall of this sac or vesicle is composed of 

 a single hiyer of large, columnar, nucleated cells, chiefly 

 remai-kable for their bright yellow colour. The inner end 

 of each cell, towards the cavity of the sac, shows indications 

 of being cuticularized and forms a slight, obtuse projection. 

 Such a saccular diverticulum of the ciliated duct appears, 

 according to Burger, to be very characteristic also of the 

 marine Enopla. Possibly, as Burger suggests, it is sensoiy 

 in function. 



h. The Eyes. 



Geonemert(s axis' valiensis diflers from all previously 

 described land jNemevtines in the possession of a large 

 and indefinite number of eyes, all the previously described 

 species having either four oi- six. These eyes, of which 

 there may be as many as thirty or forty in our 

 species, are arranged in two gronj^ (Fig. 1 2, e. (/.), one on 

 either side of the opening of the rliynchodnsum at the 

 anterior extremity of the body. Each group, containing 

 about twenty eyes of various sizes, may show indications or 

 a division into an anterior and a posterior ])ortion, the eyes 

 in the anterior portion being on the average larger than 

 those in the ])Osterior. Whether this is a constant airange- 

 ment or not 1 cannot sa}', but it suggests that the numerous 



