142 ZOOLOGY. 
These daintily feel about for the cause of the alarm, and, if 
they fail to detect the proximity of an enemy, the whole 
fascicle is cautiously pushed out, and the sentient threads 
suddenly and confidently unfolded. 
“‘The polyzoén reasons from the sense of touch inherent 
in its tentacles, and cannot be induced to expose itself above 
the cenecium until thoroughly satisfied by these sensitive 
feelers that no danger is to be apprehended. In fact, these 
plant-like creatures, singly mere pouches with a stomach 
hanging in the midst, exhibit greater nervous activity and 
‘animality,’ than we find among the more highly organized 
Ascidia, or shell-covered Brachiopoda.” 
The epistome is a fold of the lophophore, used to close the 
mouth and thus prevent the food from escaping from the 
mouth. It is tongue-like and very pliable. ‘‘The border is 
capable of a tactile motion similar to that of the human 
tongue, and it takes cognizance of what passes into the 
mouth by frequent and repeated jerks toward the aperture” 
(Hyatt). Itis situated immediately over the ganglionic mass, 
and between the anus and mouth. 
The Polyzoa, as regarded by Hyatt and others, are struc- 
turally nearly related to the Brachiopods, the higher forms 
of which, such as Terebratula and Rhynchonella, have the res- 
piratory tentacles similarly placed around the disk or lopho- 
phore, which is perforated at the centre by the mouth, and 
from which the alimentary canal hangs, “ith a dorsal flexure 
and anusnearthe mouth. ‘‘ The extension of the lophophore 
into two or three spiriform arms, the complex structure of 
the tentacles and of the muscular and nervous systems, are 
all more or less foreshadowed by the condition of these sys- 
tems among the higher Polyzoa.” On the other hand, the 
Polyzoa are closely related to the worms, the Gephyrean 
worm, Phoronis, being the connecting link. The mode of 
development of the Polyzoa and Brachiopoda are quite simi- 
lar, as will be seen farther on, and owing to these decided sim- 
larities in development and anatomy, the Polyzoa and Brachi- 
opods form a natural group or series, distinct on the one 
hand from the Rotatoria, and on the other from the mollusks 
and worms. 
