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OTTO C. GLASER 
description were found in the cnidophores of the eolid (fig. S, A). 
The complete identity of the two kinds was demonstrated by the 
discharged filaments, for these are characteristically barbed. 
Near its base (fig. 3, B), each thread has a large number of minute 
barbules directed toward the capsule. This region is followed by 
one with stouter barbs, and this in turn by one with small. The 
extreme tip of the thread is bare. Such a filament is sufficiently 
marked to make its recognition easy. 
Fig. 3 A, B, nematocysts of Sagartia and of an eolid which preys on Sagartia; 
C, D, E, three types of tubularian nematocysts found in eolids which prey on 
Tubularia. 
The most striking case which I have observed is the following : 
at Beaufort, also, another species of Eolis lives on Tubularia. 
An examination of the undischarged nematocysts of this tubu- 
larian divulges no great differences among them, but when ex- 
ploded three kinds are easily recognizable. One (fig. 3, C), has a 
long delicate thread completely devoid of barbules, and widening 
near the base where it is continuous with an almost spherical cap- 
sule. A second type (fig. 3, D), less frequent, practically dupli- 
cates the first, except in two particulars : the capsule is consider- 
ably smaller, and the thread instead of widening at its base, is pro- 
