XXVlll INTRODUCTION. 
the points directed inwards, so that food can readily pass 
into, but cannot return again from, the stomach. The 
teeth on each side appear to correspond, so that they 
probably play an important point in tearing and lacerating 
the food as it passes into the stomach. Posterior to this 

Fie. 4. 
triturating apparatus there exists four leaf-like plates, 
fringed with long and powerful cilia. These are attached 
to the lateral walls in pairs, one anterior to the other; 
immediately above the second or posterior pair, appa-. 
rently in a chamber of its own, is a gizzard-like apparatus. 
We observed this most distinctly developed in Sulcator 
and Talitrus, and we believe it to be present in all the 
Amphipoda, and we take it to be the same appendage 
which Bruzelius and Loven figure and describe as the 
‘‘mellanbalkan,’” which is situated within the “ blind- 
sacklikt organ,” and not, as their figures * would lead one 
to believe, on the floor of the stomach. 
* Ofversigt af K. Vetensk. Akad. Forhandl. 1859, pl. i., figs. 1, 3, 8. 
