412 



ANATOMY OF VERTEBRATES. 



309 



in the Marsupialia ; it is either simple, as in the Zoophagous, 

 Entomophagous, and Carpophagous tribes ; or is provided with a 

 cardiac glandular apparatus, as in the Koala and Wombat ; or is 

 complicated by sacculi, as in the Poephagans. 



It might have been expected that the stomach would have ex- 

 hibited some modifications in the development of the left or 

 cardiac extremity corresponding with the differences of food and 

 dentition observable in the large proportion of the Marsupial 

 order, in which this viscus presents its simple condition ; but this 

 is not the case : the form of the stomach is essentially the same 

 in the carnivorous Dasyure, the insectivorous Bandicoot, and the 

 leaf-eating Phalangers. It presents a full, round, ovate, or sub- 

 triangular figure, with the right extremity projecting beyond and 

 below the pylorus ; the longitudinal diameter seldom exceeds the 

 vertical or transverse by more than one-third ; often, as in Phas- 



cogale and Dasyurus viverrinus, 

 by only one-fourth of its own ex- 

 tent ; and the oesophagus enters at 

 the middle of the lesser curvature, 

 or sometimes nearer the pylorus, 

 but always leaves a large hemi- 

 spherical cul-de-sac on the left 

 side. Daubenton 1 has given illus- 

 trations of this characteristic form 

 of the stomach in different species 

 of Didelphys ; it is here figured as 

 it exists in the Phascogale, fig. 309. 

 The stomach is relatively much 

 more capacious in the carnivorous 

 Marsupials than in the carnivorous 

 Placentals. Some slight modifica- 

 tions occur in the disposition of the 

 lining membrane ; in the Phasco- 

 gale a series of very thick rugae 

 radiate from the middle of the 

 upper part of the caecal end of the 

 stomach, some of which were con- 

 tinued along; the lesser curvature 

 to the pylorus. In the Perameles 

 nasuta the internal surface of the left cul-de-sac is smooth ; the 

 right half of the stomach has rugae, running chiefly in a longitu- 

 dinal direction, and particularly numerous towards the pylorus. 



Alimentary canal, Phascogalc flavipcs. 



cxxn", torn, x, pi. 48, fig. 1. 



