102 THE ANATOMY OF THE HONEY BEE. 



anterior end of the intestine. This tube can be very easily seen by 

 carefully cutting open the outer walls of the ventriculus, but it is 

 best demonstrated by transverse microtome sections of a specimen 

 prepared for histological purposes. Such a section is shown by figure 

 46 A. A small amount of solid food matter {qq) is seen in the cen- 

 ter of the specimen, surrounding which are numerous irregular con- 

 centric rings of membrane {Pmb), some adhering to each other in 

 places, others entirely free, most of them structureless, but others 

 partly cellular. These are known as the peritropMo membranes 

 {Pmb). They keep the solid contents of the stomach away from the 

 epithelial walls, from which, as will be presently explained, they are 

 given off from time to time. 



The walls of the ventriculus (fig. 46 A) are thick and consist of 

 numerous cells {Epth) apparently very irregularly arranged. On 

 their inner surfaces is a thin intima [Int) and on their outer surfaces 

 a still finer basement membrane (BAI) . Outside of the last are two 

 layers of muscles, the external layer consisting of longitudinal fibers 

 (LMcl) and the inner of transverse ones {TMcl). Numerous an- 

 nular depressions of the walls form internal folds (fig. 45), but any 

 part of the ventricular wall can be stretched out into a flat sheet, 

 which is then seen to be full of little pits, giving the whole a screenlike 

 appearance. Sections show that the pits result from circular invagi- 

 nations of the basement membrane (fig. 46 B, BM), and that at the 

 bottom of these pockets the cells are very small and convergent, while 

 those on their lips are very large. Figure 46 B is a very perfect 

 example of this structure of the epithelium, which is usually more 

 or less obscured, as in figure 46 A, by a great proliferation of small 

 cells from the lips of the cups — and then a large section seldom gives 

 a symmetrical view of all the parts. The cups are all filled to over- 

 flowing by a gelatinous mass (pp) which fuses over their edges into 

 a continuous coating beneath the intima over the entire inner surface 

 of the epithelium. This mass appears to be formed mostly by the 

 cells at the bottoms of the cups, for the outermost of these (fig. 46 B, 

 7t) often insensibly fade into it. 



Figure 46 E shows an opposite condition of the epithelial cells. 

 Here the lip cells of the cups appear to be very actively dividing, 

 and proliferating a great number of small cells (Em) which float 

 off into the gelatinous covering. These discharged cellules are all 

 nucleated, but their protoplasm does not stain in preparations and 

 consequently they appear clear and transparent as compared with the 

 cells they apparently come from. The writer has not been able to find 

 any of these cells actually in the process of division, but a comparison 

 of figures B and E (which are camera lucida drawings and not dia- 

 grams) would certainly suggest that the condition of the cells in E 

 has resulted from a very active division of the cells of the walls and 



