ALIMENTARY CANAL IN THE BEE 511 



eminence of the bottom of the inghivies. The capitukim 

 consists of four valves between which there is a cruciate slit 

 (PL 16, fig. 5, pc). The valve is provided with three systems of 

 muscular fibres — two longitudinal (PI. 16, fig. 5, m^, Wg) and one 

 circular (PI. 16, fig. 5, m^) between them. The former serve to 

 open the valve, the latter to close it. The capituhim of the 

 valve is set on a trunk connecting it with the stomach. From 

 the circumference of the ventricular opening into the intestine 

 hangs an intestiniform cardial valvule preventing the contents 

 of the stomach from returning into the crop. All these data 

 w^ere already established by previous investigators. 



Mid -gut (Stomach). 



The stomach of the bee consists of a fairly thick cylindrical 

 tube with numerous circular constrictions on it corresponding 

 to which the epithelium of the stomach protrudes into its cavity 

 in the form of folds. The epithelium consists of cylindrical cells 

 which assume the shape of clubs on the ridges of the folds. 

 At the bottom of the depressions between them are situated 

 round groups of cells called cryptae. Exteriorly to the mem- 

 brana basilaris is disposed the connective tissue in the form of 

 small groups of cells. The muscular membrane of the stomach 

 is formed by two layers of transversally striated muscle- 

 fibres — interior circular, and exterior longitudinal. 



(fl) The epithelium of the stomach consists of cells wuth an 

 alveolar protoplasm of basophil character (PL 16, fig. 7, ej) ; 

 figs. 9, 11, 13, ep). The oval nucleus with sparse chromatin 

 granules, or a dense network of them, lies in the middle of 

 the cell. In its protoplasm are produced oxyphil granules of 

 secretion which are numerous in the superficial portion of the 

 cells. In some sections the cells appear to be set on thin 

 peduncles and to have truncated apices. This picture, as well 

 as the formation of evaginated swellings on the surface of 

 the cells, is in most cases artificial (PL 16, fig. 12, hi). 



The superficial layer of protoplasm of the epithelium is 

 transformed into a fairly broad band vertically striated and 

 bearing the aspect of a brush of cilia (PL 16, figs. 9, 11, 12, wp). 



N n 2 



