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T. DE MONTE AND G. PILLERI 



Geraci; Newman & McGeer; Ridgway, 1965; Ridgway et al., 1968). This 

 may be due either to the predominantly proteinic diet or to the need to maintain, 

 in an organism constantly immersed in water, an osmotic balance with the envi- 

 ronment. The electrolytes that have been found to resemble both in quality and 

 quantity those identified in Man (S. Andersen; Eichelberger et al.; Medway & 

 Moldovan; Medway & Geraci; Malvin & Rayner; Ridgway, 1965; Ridgway 

 et al., 1968) could not, by themselves, provide sufficient compensation for the 

 considérable différences in osmotic pressure between the body of the animal 

 and its environment (river or sea water) where electrolytic concentrations vary. 



The protein and lipid metabolism of cetaceans is considerably more active 

 than that of terrestrial mammals due, on the one hand, to the energy required 

 by the muscular masses that are continuously in motion, and on the other, to the 

 necessity of maintaining body température at an adéquate level regardless of 

 the thermie condition of the water in which the animal is immersed (Slijper). 



It should also be pointed out that the values calculated by us reflect the mode 

 of capture of the animal. There is no doubt that stress and trauma resuit in 

 higher blood urea levels. We are in possession of data that has not yet been 

 published on Delphinus and Stenella, some of which were captured with a harpoon 

 and some by electroanesthesia. Thèse data show that the mean blood urea values 

 in the animais captured by the latter method are slightly lower than those found 

 in harpooned animais. 



The mean blood urea values calculated by us for Inia are less than 1 g%o. 

 Thèse are the lowest values found by us to date in the différent species of 

 cetaceans examined by identical methods {Inia, Platanista, Stenella, Delphinus, 

 Grampus, Phocoenoides, Eschrichîius). 



Although it has been established that différences exist in the blood urea 

 values of P. indi and P. gangetica, it is not possible to compare the urea level of 

 Platanista with the levels determined for the other cetacean gênera examined by 

 us. The blood urea of the two species of the genus Platanista was determined 

 from plasma, while the other analyses were performed on whole blood. We 

 intend to correct thèse values by determining, in the near future, the blood urea 

 of the live Platanista spécimens transported by Pilleri from Assam to the dolphi- 

 narium of the Brain Anatomy Institute in Berne. 



At the time of writing it is impossible to state whether or not the urea value 

 is lower in river cetaceans than in marine cetaceans. 



CHOLESTEROL 



Several authors (S. Andersen; De Monte & Pilleri, 1968c; Medway & 

 Geraci; Newman & McGeer; Ridgway, 1965; Ridgway et al., 1968) have 



