SOME INTERNAL STRUCTURES 63 



of their stomachs is large, and from it lead from the 

 opposite extremity, be it remembered, to that where 

 the oesophagus enters 6-13 smallish, round, orange- 

 shaped cavities of which the last, that immediately 

 preceding the duodenum, is often the largest. It 

 is so, for instance, in Mesoplodon bidens. What, then, 

 is the exact correspondence between the stomachs 

 of these whales and those of the dolphins and whale- 

 bone whales ? The inevitable conclusion is that the 

 first compartment of the latter whales is missing in 

 the stomach of the Ziphioids. This conclusion is 

 not only supported by a comparison of the actual 

 structures concerned ; as is so often the case, the 

 solution of the problem is aided here by those occa- 

 sional occurrences, so useful to the morphologist, 

 of rudiments. In Hyperoodon Dr. Jungklaus has 

 detected a small representative of the first stomach 

 of other whales in the form of a slight caecal dilata- 

 tion of the oesophagus just before it opens into the 

 normal first stomach of that whale. This rudiment 

 seems obviously to have the significance that he 

 suggests. And, moreover, it showed internally a 

 characteristic meandering arrangement of the folds 

 of mucous membrane, an arrangement which is 

 universal, or nearly so, in the first division of the 

 stomach of dolphins. It appears, therefore, that the 

 stomach of the Ziphioids is to be derived from that 

 of dolphins, and not vice versa. This is in harmony 

 with other considerations, which point to the 

 Ziphioids as modified, not archaic, forms of whales. 

 (See below.) 



