luj (library''^ 



Ak'I'. XV. — Oy/ the Sfractiire of IloUn/lwa dubia, an 

 Oiyanisni of iJotihljvl a^nity. 



By BAT.DWJN SPENCER, M.A., C.M.(i., F.R.8., 



Professor of Hiolotry in the Melhourne University. 



(With Plates XXIV\, XV.). 



[Read lOtli September, 1!)0H.] 



In Fel)ruary. 1905, Dr. T. S. Hall collected at Lome, on the 

 shores of the southern coast of Victoria, a few specimens of a 

 small oreanism that had evidently been thrown up during heavy 

 weather in Bass Strait. From that time to this no further speci- 

 mens have been ol)tained. Dr. Hall was unable to preserve 

 many, and the fourteen that he did secure Avere preserved in 

 formalin, and remained unnoticed until recently in the store col- 

 lections of the Biological Laboratory in the Melbourne L^niver- 



sity. 



The general apj)earance of the organism suggested at first 

 glance an alliance with the Ctenophora, but what appears on 

 superficial examination to be of the nature of ctenophoral bands 

 tr.ru out, on minute examination, to have nothing whatever to 

 do with those, and not to possess the slightest trace of cteno- 

 phoral plates or canals. 



I thought at one time that the organisms might be detached 

 parts of some larger form specially modihed individuals of 

 some colonial animal but careful search reveals no trace of any 

 such separation having taken place, and I can only conclude, 

 therefore, that they represent a stage in the life history of some 

 form which is at present unrecognised ; possibly, as will be sfnm 

 later, a nurse stock. 



Their structure is at once simple, definite and remarkable, 

 and, in certain respects, (piite unlike that of any orofanism at 

 jiresent described. 



Each has taken the form of a mass of stiff jellv with four 

 sides and an oral and alxtral end. (Figs. 1. 2, 3, 4.) Everv 



