228 THE AMERICAN: NATURALIST. = [VOLV XXXII. 
other author has been able to demonstrate this certainly unique 
and surprising arrangement. Neither could I find the muscle 
bundles and ganglion cells of von Lendenfeld, although this 
purely negative evidence should not be allowed to have much 
weight. The adhesive cells were found in several species of 
Aglaophenia, and observed in action ; the observations confirm 
very decidedly the description given by their original describer, 
von Lendenfeld. 
There has been considerable re concerning the prob- 
able use of the sarcostyles. My own observations on the 
living organisms would indicate that they serve several distinct 
functions. 
ist. Defense. In many cases, especially in the genera 
Aglaophenia, Lytocarpus, and Cladocarpus, the distal part of 
. the sarcostyle contains a battery of very large and formidable 
nematocysts or stinging cells. The threads of these cells are 
projected all together when a large or dangerous enemy ap- 
proaches too near the adjacent hydranth. It is probable that 
the cnidocils of these nematocysts must be touched before the 
battery is discharged. Some species of Lytocarpus have such 
effective batteries that their sting is severely felt through the 
-human cuticle, a very unusual thing among the Hydroida. The 
nematocysts themselves do not leave the nematophores when 
their threads are projected. 
2d. Prehension of food. This is effected by the adhesive 
cells, which are situated on the extensible part of the sarco- 
styles of many species. Von Lendenfeld gives an excellent 
description of the capture of small crustacean zoæa. From 
his account it appears that the prey is first paralyzed by the 
nematocysts in the tentacles of the hydranths, and then secured 
by the adhesive parts of the adjacent sarcostyles which stick 
firmly to the smooth chitinous covering of the crustacean. 
After this attachment is formed, the contraction of the sarco- 
style brings the victim again within the reach of the tentacles, 
which convey it to the mouth of the hydranth. 
3d. The removal of refuse or decomposing organic matter. 
This function of the sarcostyles has been suggested by several 
