GYMNOSOMATOUS PTEROPODA 
397 
processes, only one being in motion at a time, and the moti- 
lity seemed to be in the distal part only (fig. 5, a.) The 
probosciform opening is divided intotwo parts by a médian 
latéral pair of lips. Inside of these is a pair of hooked prehen- 
sile organs laterally placed. They were sometimes protrud- 
Fig. 4.—Drawing fromlife of Tnchocyclus hansine'énsis [sp.nov.], dorsal view, (Compare 
with figures 1 and 3.) 
ed very rapidly and withdrawn simultaneously with a 
Swift inward stroke. In this act of scooping, they were 
arched. Sometimes only one was working from its side 
being protruded for ward and withdrawn successively withoiit 
its member of the opposite side being visible. The head is 
set ofî from the body with a short but distinct neck. 
Fins:—The fins extend laterally from the ventral side of 
