492 FREDERIC T. LEWIS 



passes along this curvature from the oesophagus to the pars 

 pylorica. A more distinct canal in this position is seen in two of 

 Broman's models, from embryos of 10 mm. and 16.2 mm. respec- 

 gively. Apparently this canal has not been previously described 

 in embryos, although Toldt (1879), referring to the general 

 direction of the oesophagus in a 23-mm. specimen, states that it 

 descends into the stomach "in such a way that the lesser curva- 

 ture forms, as it were, a continuation of the ventral border of the 

 oesophagus." 



In the embryos of 19.3 mm. and 19.0 mm. shown in figures 

 7 and 8 respectively, the canal is not seen. The first of these 

 stomachs is abnormal, but the second specimen is unobjectionable.* 

 Moreover in Broman's figure of the stomach from an embryo of 

 21 mm., there is no trace of the channel. Its obliteration, if 

 normal, appears to be temporary however, for in the 44.3-mm. 

 specimen shown in figure 9, it is more distinct than in preceding 

 stages. It passes from the conical cardiac antrum to the angular 

 incisure. This embryo, owing to its large size, was not perfectly 

 preserved, and the epithelium has separated from the mesen- 

 chyma; but whether one, or the other, or both of these tissues has 

 shrunken is uncertain. The model may, however, be accepted 

 as giving an essentially correct idea of the shape of the stomach, 

 since the separated mesenchyma presents corresponding ridges 

 and furrows. The distinctness of the gastric canal is strikingly 

 shown when the model is viewed from the inside (fig. 10) . It takes 

 a slightly S-shaped course from the stellate cardia to the orifice 

 of the pars pylorica, and is bounded by a rounded plica aortica, 

 and a more prominent and angular plica hepatica. These folds 

 are not formed, as described in the adult by Hasse and Strecker, 

 through compression of the border of the stomach between the 

 aorta behind and the caudate lobe of the liver in front; for the 

 outer layers of the stomach are not indented. Moreover at this 

 stage there are no bands of oblique fibers to account for the canal. 

 If the channel proves to be a constant feature of embryos of this 

 stage, and it is present in an embryo of 37 mm. which was not 

 modelled, it may be that the arrangement of the oblique fibers is a 

 consequence rather than the cause of the gastric canal. 



