THE ALIMENTARY CANAL AND ITS GLANDS. 105 



most of a year, are confessedly not nearly adequate to serve as a 

 basis for conclusive statements on the digestive process. They are 

 sufficient, however, to show the utter lack of a basis in facts for many 

 other opinions on this subject. 



Cheshire (188G) describes two kinds of cells in the ventricular 

 epithelium, '■'•one secreting a digestive fluid (gastric juice) from the 

 surrounding blood into the stomach, so that the pollen grains may be 

 made fit for assimilation by a transformation not unlike that lique- 

 fying gluten in our own case; the other absorbing the nutrition as 

 prepared and giving it up to the blood." Though Cheshire refers 

 to his figures to show these two kinds of cells, he does not point out 

 which are which — in fact, he does not even designate two different 

 kinds in his drawings nor even represent two kinds. 



The small intestine (fig. 42, SI iit) forms a loop upon itself and con- 

 stitutes a narrow tube connecting the stomach {Vent) with the large 

 intestine or rectum {Rect). Its anterior end is somewhat enlarged 

 and carries the circle of malpighian tubules {Mai). Its epithelium 

 (fig. 46 D, Epth) is very simple and is thrown into six longitudinal 

 folds that jjroject into its lumen. On the outside is a thick sheath 

 of transverse muscle fibers {TMcl) with distinct nuclei (.V?^). The 

 latter are designated by Cheshire (1886) as "longitudinal muscles" 

 (see his figure 14 D), but this is a very evident mistake — the small 

 intestine has no longitudinal muscles at all. It is evident that the 

 folds of the epithelium permit the ordinarily narrow tube to expand 

 very considerably when necessary to allow the passage of a large 

 amount of food. The contents of the small intestine are usually 

 drier than those of the ventriculus, consisting principally of masses 

 of partly digested pollen, that is to say, the contents of the grains are 

 partly dissolved out — presumably signifying that they are under- 

 going digestion. There is usually only a small amount of the brown 

 slime present such as fills the ventriculus. 



The Malpighian tubules (fig. 42, Mai) are wa^apped and coiled about 

 one another and about the viscera of the abdominal cavity. There 

 are about 100 of them in the honey bee and they all open separately 

 into the anterior end of the intestine. Each is a very long thread- 

 like tube consisting of a single layer of epithelial cells provided with 

 a very delicate basement membrane and intima (fig. 46 C). The ends 

 of many of the cells are clear and bulge into the lumen. Figure 

 46 G shows a section through the junction of the ventriculus and the 

 intestine where the tubules open by narrow necks penetrating the 

 epithelium. The wall of the ventriculus forms a short double-lnyered 

 fold {VentVJv) projecting backward into the anterior end of the 

 intestine, behind which are the orifices of the Malpighian tubules. 

 The section from which figure G was drawn is cut somewhat obliquely 

 and takes in this fold only on one side. 



