148 The Ohio Journal of Science [Vol. XXI, No. 5, 



PART V. 



GENERAL SYSTEMATIC SURVEY OF THE MACROFAUNA WITH NOTES 



ON THE VARIOUS SPECIES.* 



Phylum PORIFERA. 



Spongilla fragilis Leidy. Fresh-water sponge was found on 

 only one of the large, submerged stones, on the north shore 

 of the large pond. The flat, gray, incrusting colonies were 

 irregularly rounded, filling the uneven depressions of the lower 

 surface. 



Phylum CCELENTERATA. 



Hydra viridissima Pallas {H. viridis L.), was found, but was 

 evidently rare. 



Hydra oligactis Pallas, {H. Jusca L.), was somewhat better 

 represented. Undoubtedly it was more common at times than 

 these collections showed. 



Phylum PLATYHELMINTHES. 



Class TURBELLARIA. 



Planaria gonocephala Duges, was the only species of the 

 Tricladida found, and the few specimens were all from the 

 lower surface of a large, fiat, submerged stone, on the north 

 shore, station 7. 



The reason for the meagre lot of individuals and of species 

 of flatworms, was the insufficient and unvaried food supply. 



Dalyellia sp. was found merely by accident in examining 

 some pond w^ater microscopically. This and others of its group 

 were very likely common in parts where algae abounded. 



Phylum NEMATHELMINTHES. 



Class GORDIACEA. 



Paragordius varius (Leidy). One adult found in algae near 

 the water's surface in the small pond was the only represen- 

 tative of the group taken in the entire survey. No special 

 search was made for the parasitic larvae. 



* For the numbers of specimens of all aquatic species found at the various 

 stations, see the Table. 



