■332 PROCEEDINGS OF SECTION D. 



Friday, August 31. 



The President, Mr. Ralph Tate, F.L.S., F.G.S., Professor of 

 Natural Science in the University of Adelaide, in the Chair. 



The following papers were read : — 



1.— PRELIMINARY NOTES ON THE STRUCTURE AND 

 DEVELOPMENT OF A HORNY SPONGE {STELO- 

 SPONGUS FLABELLIFORMIS). 



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



2.— PRELIMINARY OBSERVATIONS ON THE MINUTE 

 ANATOMY OF AN AUSTRALIAN PLANARIAN. 



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



3._0N THE DEVELOPMENT AND STRUCTURE OF 

 THE PINEAL EYE IN HINULIA AND GRAAIMA- 

 TOPHORA. 



By William J. McKay, B.Sc, Sydney. 



\^Ahstract.^^ 



The observations contained in this paper were made at the 

 Biological Laboratory of the Sydney University, through the 

 kindness of Dr. W. A. Haswell, whom I have to thank for directing 

 my attention to the subject, and for a portion of my material. 



The material I have had, has been various stages in the develop- 

 ment of Hinu/ia (Lygosoma) tasniolata, Hinulia sp., and Gram- 

 'inatophora (Amphiboktrus) muricata. In the embyros of Hinulia, 

 the pineal eye stands out as a prominent projection in the region 

 of the thalamencephalon ; while a smaller projection immediately 

 behind it is the curved end of the epiphysis. In Grammatophora 

 the epiphysis is seen in the first stage as a simple evagination of 

 the wall of the thalamencephalon, being composed of a single 

 row of columnar cells. In the next stage the outer wall begins to 

 grow forward and leads to the formation of a second evagination 

 in the wall of the primary one. There are thus formed two 



