AQUATIC MAMMALS 



are secreted, and apparently these are regurgitated into the first division. 

 Indigestible matter, like cuttlefish beaks, is probably vomited forth, from 

 time to time, but the gastric juices are doubtless capable of dissolving 

 fish bones. At any rate the stomach contents must be thoroughly liquefied 

 before leaving the second division for its exit is minute and of little 

 greater diameter than that of a stout probe. The third and subsequent 

 division appears to be nothing but a specialization of the pylorus, con- 

 torted and with several constrictions. 



The cetacean intestinal tract is not usually remarkable and is of mod- 

 erate length. Owen (1868) quoted Hunter to the effect that in a 

 Balaenoptera acutiro > strata 17 feet long the total intestinal length was 

 93-3/4 feet. But on the other hand the same author stated that in 

 Hyperoodon the whole intestinal canal was sacculated in a surprizing 

 manner. 



The stomach of the dugong is remarkable for being very thick and 

 muscular, and for having two caecal appendages or diverticula. Owen 

 gave the intestinal length of a half -grown individual as 27 feet. The 

 caecum of this animal is single, but it is bifid in the manati. 



The stomach of the Pinnipedia is not particularly noteworthy but the 

 intestinal tract is of phenomenal length. Engle (1926) has recorded a 

 sea-lion (Eumetopias) with intestinal length of 264 feet, which is over 

 twice as long as has been reported for a fur seal (107 feet). Stones 

 of considerable size and of an aggregate weight of several pounds have 

 been reported as found in the stomach of sea-lions. It has been sug- 

 gested that this is for the purpose of weighting down the animal, but I 

 would regard this added weight as insignificant to a body weighing sev- 

 eral hundred pounds. More attention should be paid to the time of 

 year at which stones are or are not present, and if both sexes are so 

 equipped. If they should prove to occur only in males during the mat- 

 ing season then it might be inferred that they are for the purpose of pre- 

 venting undue atrophy of the stomach, through functioning as a sort of 

 gastric "chewing gum," during the many weeks that this sex is without 

 food while guarding the harem. 



URO-GENITAL SYSTEM 



Potentially there is much to be done on the urinary system of the ma- 

 rine mammals. A fundamental question is how do these creatures get 

 the water which they must drink. If they obtain it by drinking sea water, 

 then how do they eliminate the excess of saline matter, which they would 

 be obliged to accomplish by some specialized means? Actually, how- 



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