66 SECOND GENERAL MEETING. 



common alike to the independent collared monads and the essential 

 flagelliferous sponge elements : how that this structure is an 

 exquisite funnel-like trap for the arrest of food particles, and how 

 within its substance a continuous outward and inward flow of its 

 constituent sarcode is maintained, as obtains in the attenuate pseudo- 

 podium of Gromia and other typical Rhizopods. In addition to this, 

 each of these collared elements, whether belonging to the independent 

 monads or to the sponge aggregations, were found to possess 

 posteriorly two or more very distinctly-defined contractile vesicles, 

 which dilate and collapse with rhythmical regularity, after the 

 manner of the corresponding vesicles or rudimentary excretory 

 organs that are characteristic of all of the ordinary flagelliferous 

 and other Infusoria. 



Now, however much the sponge body may be complicated by 

 the development of intricate canal systems or by spicular or other 

 skeletal elements, which are actually non-essential, the very fact 

 of the possession in common by the sponges and by the flagelliferous 

 Protozoa of these very peculiarly modified cell elements, which are 

 found nowhere else throughout the animal kingdom, must, I think, 

 carry with it the assumption that a very close phylogenetic relation- 

 ship subsists at all events between these two groups. 



The tendency of late years has been to correlate sponge struc- 

 tures with Coelenterata, and unfortunately none of the many eminent 

 authorities who have decided in favour of this interpretation have 

 given any special attention to the life-history and organisation of 

 that peculiar group of the Collared Flagellata to which the sponges 

 are apparently related. Since, in fact, the regretted deaths of 

 Stein, Carter, and H. James Clark, the field of investigation opened 

 up by their labours has been practically abandoned, and, so far as I 

 have been able to ascertain, there is but a single authority who has 

 made a critical examination and fully verified the facts recorded by 

 myself eighteen years ago concerning the precise function and 

 significance of that exquisitely translucent collar-like structure that 

 is shared by both the collared monads or choano-flagellate, and 

 the essential sponge elements. That authority is an American, Mr 

 S. Foulke Andrews, and the confirmation referred to is contained 

 in a very elaborate and painstaking essay entitled " The Living 

 Substance," published at Boston so recently as the year 1897. 



What I would urge as most reasonable is, that this vexed 

 problem of sponge affinities should be fairly approached and 

 examined from a protozoic as well as from a ccelenterate basis, and 

 that those undertaking the task should familiarise themselves with 

 both the collar-bearing flagellata and the corresponding sponge 

 elements in their living state. 



So far, all of the many elaborate and exquisitely-rendered repre- 

 sentations and descriptions of sponge tissues have been derived 

 from preserved specimens in which the very characteristic life 

 aspects and contours of the essential collar-bearing elements are 



