502 
MR. OSLER’S OBSERVATIONS ON THE ANATOMY 
and dividing a delicate expansion down the groove which the tongue had occu- 
pied. The divided membrane will immediately slip down, and expose a pair 
of elastic bodies, set, like acorns in their cups, in a thick base, from which this 
membrane is expanded to cover them. A process from the base is given off 
from between them, forming a loop, through which the tongue passes. The 
elastic bodies are narrowed in front, where they are connected by a vertical 
band ; and they are. united to the base in which they rest, only at a small 
point anteriorly, their larger posterior portions being free. The apparatus is 
represented, fig. 7, in which the elastic bodies are separated to show the mem- 
brane which connects them in front. 
The tongue, a flat strap-shaped organ, is more than two inches long. It 
presents three longitudinal ranges of teeth, which recline backward, and are 
set like scales, with very little elevation of their edges. In the two outer rows, 
the teeth are single, irregularly crescentic in shape, and set by their convexity : 
in the middle one, each transverse range contains several, which are small, and 
nearly square. All are too minute to be distinguished, except under a high 
magnifying power. The magnified lingual membrane appears beautifully reti- 
culated. 
From a consideration of the whole structure, the action of the parts may be 
readily inferred. The contraction of the broad muscles brings the lower and 
posterior part of the fleshy mass forward ; and the tongue, thus thrown back- 
ward with a circular motion, will act effectively upon the food which the ex- 
ternal lips have brought within its range. It is probable that the contraction 
of the columnar muscles of the pharynx is synchronous with this motion, as 
the opening into the oesophagus would thus be advanced to receive the por- 
tion cut away. The reaction of the elastic bodies, which are necessarily 
compressed in effecting the stroke, will restore the parts to their former po- 
sition. 
Turbo littoreus feeds upon the softest algae. I have observed it devouring a 
minute filament, which entered the mouth by a succession of jerks, repeated at 
very short intervals. In this case it is probable that the filament passes undi- 
vided into the stomach. When browsing upon larger fragments, the portions 
cut away are so very small that the impressions left can be seen only by a close 
inspection. 
