G.H.Park 



arker 



haring ('98, p. 18) believed themselves justified in declaring that 

 the cells of sponges "are not connected in a way so as to enable 

 them to conduct stimuli from one cell to another" and that these 

 animals are therefore "destitue of the principle, the significance 

 of which culminates in nervous tissue." It was the chief purpose 

 of the investigations recorded in the present paper to ascertain 

 whether there was any physiological ground for the assumption 

 that sponges possess a nervous system, or whether from the stand- 

 point of their activities, as well as of their structure, they showed 

 no evidence of nervous organs. The general inertness of sponges 

 has doubtless long deterred investigators from attempting a studv 

 of their reactions, and it must be confessed that even on close 

 examination they show only a few form of inconspicuous response 

 These few types of movement, however, are of considerable 

 interest, for, as the following account will show, they throw con- 

 siderable light not only on the question of the nervous system, in 

 sponges but also on the still more fundamental problem of the 

 origm of the nervous system in general. 



The species on which my work was done was Stylotella helio- 

 phila Wilson, a monaxonid demosponge belonging to the order 

 Helichondrina. This species will be described m a monograph 

 on the sponges of Beaufort, N. C, soon to be published by Dr. 

 H. V. Wilson, and I am indebted to Dr. ^^ilson for having called 

 my attention to this sponge, which in all respects was extremely 

 satisfactory for the work I had planned. My investigations were 

 carried out in June and July at the Beaufort Laboratory of the 

 United States Bureau of Fisheries, and I am under obligations to 

 Commissioner G. M. Bowers for the privilege of working at this 

 laboratory and to its director, Mr. H. D. Aller, for generous pro- 

 vision during my stay there. 



2. STYLOTELLA UNDER NATURAL CONDITIONS 



Stylotella heliophila is found in great abundance in the shallow 

 water near the Beaufort Laboratory. It grows in masses about 

 as large as a double fist and is attached to stones, oyster shells, 

 and like materials. It is dirty orange-yellow or greenish yellow 



