Secretion of the Stomach 57 



subside. In the middle and hinder part the epithelium 

 is sometimes thrown into shallow folds of irregular 

 shape, which, when seen in face, look like islands with 

 intervening channels (fig. 42, i). The epithelial cells 

 here assume a character which is usual in the stomach 

 of insects, though by no means peculiar to it, being 

 drawn out into numerous filaments, which are some- 

 times very long'; they may resemble, when contracted, 

 the ' striated hem ' usual in the intestinal epithelium of 

 vertebrates. 



Fio. 43. — Epithelium of stom.ach, showinfi^ jirotrusions and detacheil peri- 

 trophic membrane. Tlie striated hem is not drawn. 



Protrusions from the p-landular epithelium of the Secretion 

 stomach (such as those described and figured by stomach. 

 Gehuchten in the larva of Ptychoptera) are easily seen 

 at certain times in the stomach of the Chironomus-larva : 

 they are finely granular, and protrude through the striated 

 hem (fig. 43 \ In an earlier phase the granular substance 

 (mucigen) collects along the inner face of every cell, and 

 is readily distinguished from the ordinary cell-protoplasm 

 in which the nucleus lies ^. During active secretion large 

 drops of mucus are squeezed out, and blend with the 

 drops from neighbouring cells to form a viscid mass. 

 Empty cells, with only the basal protophism and the 

 nucleus, are occasionally but rarely seen. We agree 

 with Gehuchten in believing that the secreted fluid 



' Frenzel, 1885. - But soo noto to p. 60. 



