0)1 an. Austral i(Ln Land Nemevtine. Ill 



eyes of G. auxtraliensis nmy liave been derived by sub- 

 division of four eyes, two huger anterior ?aid two smaller 

 posteiior, such as we find in G. chalicoplova. Sometimes 

 the eyes in our species app^'ar more or less elongated and 

 sometimes even dumb-bell shaped, which seems to indicate 

 that they multi})ly by division. 



In its minute structui'e each e3^e agrees in the main with 

 the eye of Dre/'amrphorus rubrodiiatus as figured by 

 Biirger,* but I have not been able to make out so much 

 histological detail as that observer. Each eye (Figs. 1 1, Ikt) 

 has the form of a deep cup wdiose opening is turned towards 

 the surface of the body. The wall of the cup is made up of 

 a layer of elongated columnar rods, the inner ends of which, 

 next to the cavity of the cup, are perfectly clear and 

 transi)arent, while theii- outer ends are tilled with pigment 

 granules. In Dreijanophorus, on the other hand, the 

 pigment is statcicl to lie not in the rods themselves but in 

 pigment cells situated behind them. There is also a layer of 

 nucleated celk behind (outside of) the pigmented ends of the 

 rods in Gei»i emeries (Fig. 11) but this appears merely to 

 form a kind of ca])sule whose cells are perhaps also more or 

 less pigmenttMl. The cavity of the optic cup is filled with a 

 non-staining material which in transverse sections at)pears 

 finely and regnlarly i^ranular (Fig. 11a). In front of 

 the opening of tiie cup lies the oj)tic ganglion {¥\g.\\,op.g.), 

 from whicli exti-emely delicate fibrils run down into the 

 cavit\' of the cup, doubtless to become connected with the 

 inner ends of the rods, as in Drepanopliorus. The nuclei of 

 the ganglion cells are very easy to make out but not so their 

 protoplasmic bodies. I have not succeeded in tracing the 

 optic ganglion into connection with the nerves given off from 

 the dorsallobes of the cerebral ganglion (Fig. 4, n.) but doubt- 

 less such a connection exists as in other Nemertines. 



The colour of the eye-])igment is black in the living worm 

 and on the addition of dikite hydrochloric acid it turns to a 

 rich reddish l»rown colour and |)artially dissolves. 



i. Connective Tissue, Glandidar Structures, c(:c. 



The connective tissue, which fills all the interspaces 

 between the various internal organs, agrees very closely 

 with what has been described in other Nemertines. It 

 consists of an almost perfectly hyaline, transparent, non- 



* Loc. cit. Plate VI. Fig. III. 



