The author hi-hl that " water fleas"" when eoir.iiii;- in cori- 

 taet with the tentacles of JL/h-rr were s-kloni kiih'd or even 

 |)aralyz:ecl lev any leniith of time wvA t!iat t!iey often acted 

 in the s-anu" Avay \vhen touclied l)y an\ unfamiliar ohj-ct. 

 'rhc difficulty of provokinuf a diseharife of nematocxsts hy 

 nieehanieal stiuudus was meiitioned and ex{)erimeivts and 

 observations on Hviuu- corals relaled. 



Tlu' author denied t'.iat tlie tlu'eads wcrc^ projected with 

 li,i;-htninij--like rapidity, as statt^l l>y A'^-assi/. and others. 



The nuinner of projection was discnss;'d at sonte len.;th, 

 and it was considered pro!>al>le tliat it was l>y partial ever- 

 sion. 



The m(H-hai)isiii ol thescr cells was touched upon as o.Teriuir 

 iuterestin,i>' meclianieal problems not yet solved. 



The iiematoe^sts are thoui;-ht to oriiiinate in the nucleus 

 of eetodermal cells, and the author thouirht that scvei-al some- 

 times originated in one cell. 



The ap[)arent absence of nen)atoeysts in GorffoHrhr was 

 announced and the .systematic imi)ortanee of this fact insisted 

 upon. 



(The paper was illustrated by sketches by the author.) 



THE FERNS OF MUSCATINE COUNTY, IOWA. 



I,V. PROF. F. M. WrrTF.R. 



•.Af'stract.) 



The followino- ferns have been lujted or collected by me in 

 Aluseatine County. They are included in thirteen genera 

 and twenty species: 



Adtantum pedatum, Aspidium aclirosticoides, Aspt'rlnon gold- 

 ianuni* Aspidium thelypteris^ Aspidium spinulosum, Asple- 

 nium felix-fcetnina, Asplejiium. angustifoUum^ AspJenium tlie- 



* 'Ihe correctness of this determination is somewhat questionable. — Kditou. 



IPkoc. I. r S., 1SS7-9.I [NJarch 10, iSoo.) 



