DIGESTIVE TRACT OF THE CAT. 



89 



compared to the (U mm. embryo (Fig. 22). It reached about 

 one fifth of the distance between the broken and dotted hnes, 

 as shown in Fig. 19. 



The Effect of the Growth of Certain Lobes upon 

 the Neighboring Organs. 



Now that we have examined each of these hvers indi- 

 vidually, let us consider certain points wherein they differ 

 from each other, and the manner in which these differences 

 affect the adjoining organs. 



In Fig. 21, embryo 1T| mm., the stomach and duodenum 

 might be described as being contained in a great fossa which 

 is almost surrounded by liver tissue. In Fig. 22, (U mm. 

 embryo, these borders have grown apart and the fossa is 

 disappearing. In Fig. 28. Ill mm. embryo, the separation 

 of the liver borders is still more marked, until finally in the 

 adult. Fig. 18, the fossa may be said, comparatively speak- 

 ing, to have disappeared. This transformation in the shape 

 of the liver is probably largely due to the development of 

 the intestines. In embryo 1T| mm., the intestines were 

 extra-abdominal, and so the liver only enclosed the stomach 

 and duodenum, whereas in all the other embryos they were 

 intra-abdominal, and were steadily growing in size as well as 

 in length. The body of the embryo was of course also sub- 

 ject to growth, and so the liver was allowed to change its 

 shape, to accommodate itself on the one hand with the 

 growth of the intestines and on the other with the growth 

 of the abdominal cavity. As has already been stated, the 

 the shape of the liver is prone to great variation, and when 

 one reflects that the coils of intestine are pressing upon its 

 caudal surface, it is reasonable to conclude that any change 

 in the shape of this organ would affect the arrangement of 

 these coils. It consequently might seem far more curious 

 had we been able to determine any definite arrangement of 

 them than an absolute lack of it. 



A glance at the four liver plates shows that the caudate 



