Il6 ANDREWS. 



standpoint a missing link between Protozoa and Metazoa. 

 From the standpoint formulated by my facts, from the stand- 

 point of the substance, it is now seen to be even more valuable 

 as a link between these two, and as a most expressive type of 

 substance life writ larger than common. 



There is a Heliozoan described by Leidy and others, Raphi- 

 diophrys elegans, which lives at times as isolated individuals, and 

 then again, for variably long or short periods, in coalescence 

 with others to form a wandering colony. 



As single individuals, the animal does not differ from all 

 typical Heliozoa. Its filose pseudopodia are used for locomo- 

 tion, for prehension of food, for tactile purposes, — for what 

 else we simply do not know. In its isolated state, these proc- 

 esses are freely produced on all sides of the periphery, and are 

 on all sides alike in kind as in origin and function. 



In the coalesced, or compound, state, the individuals form a 

 colony whose units are separated from, as they are joined to, 

 each other by bands or bridge-like extensions of protoplasm 

 which are formed by modification of the usual processes and 

 make living links between the animals. Between these bands 

 the water surrounds the colony everywhere. 



The remarkable thing is that no matter what may be the 

 number of individuals so coalesced, and Leidy states colonies 

 contain at times upwards of thirty (I have not seen so many), 

 the usual filose pseudopodia are formed only at the periphery 

 of the whole mass. That is, each RapJiidiophrys lays aside, 

 for the term of its union with the others, the habit of filose 

 formation at all those portions of its mass, which, though 

 peripheral still to itself, are not peripheral to the colony as 

 such. From those portions of each unit, which, through coa- 

 lescence, become in a sense interior to the colonial mass, there 

 are produced only bands or bridges of thick protoplasm, both 

 ectosarc and endosarc in their usual relations to each other, 

 and these form the ties between the individuals. Those units 

 which are wholly internal to the colonial mass, produce no 

 filose processes but only connecting bands. 



Two points of utmost weight must be given due emphasis in 

 studying this physiological marvel. First, that the substance 



