Some Sponges of the Ohio River. 187 



and sometimes in deeper water. They are not infrequently brought 

 to the surface by dredging. The collections may be preserved in 

 alcohol or by drying. But as the species can only be determined 

 by examination with the microscope, it is very desirable to have 

 preparation ready for observation. Before mounting the siatoblasts 

 or indeed any part of the sponge it is necessary that the specimen 

 should be rendered transparent. This is most readily accomplished 

 by soaking the part to be mounted for several hours in glacial car- 

 bolic acid, made fluid by slight heat. When sufficiently clear the 

 specimen may be mounted in Canada balsam without previously 

 drying, as the acid and balsam mix readily. Skillful operators can 

 prepare very interesting sections of the statoblasts, or the spicules 

 may be entirely cleaned of all organic matter and mounted 

 separately. 



The following sponges were found in the Ohio river, during 

 the past autumn, about twelve miles below Cincinnati : 



Spongilla lacustris, Linn. — on rocks. 



Spongilla fragilis, Leidy — 0!i snags. .. , 



Meyenia leidyi, Potts — on snags and rocks. 



Heteromeyenia (Sp. ?) — on gravel. 



Carterius tubisperma, Mills — on gravel or rocks. 



It is not likely that this exhausts the list of species to be found 

 in our neighborhood. Indeed it is to be hoped that further ob- 

 servation at other points upon the Ohio, as well as on the Licking 

 and the two Miamis may result in many interesting finds. 



