CHYLIFEROUS SYSTEM. 



419 



diversities of character, and grades of development in the 

 different classes. 



From the white serous condition of the blood in the in- 

 vertebrated classes, resembling the limpid transparent chyle 

 of the oviparous vertebrata, several parts of the former 

 animals have been taken for their chyliferous system, 

 as the mesenteric veins of echinoderma by Monro, the 

 radiating prolongations of the stomach of medusa by 

 Carus, the biliary tubes of insects by Sheldon, and even 

 the nervous system of conchifera by Poli. In the red- 

 blooded animals it is easy to distinguish, by the difference 

 of colour, size, structure and mode of ramification, the 

 numerous plexuses of chyliferous vessels spreading upon 

 the intestine or between the folds of the mesentery, as seen 

 in the annexed view (Fig. 131. h. i. k.) of those of the small 



FIG. 131 



intestine of the tortoise. They accompany the veins (131. 

 c. d. e.) and the arteries (ISl.y. g. I.) in their course along 

 the mesentery to the thoracic duct (h.) ; but much exceed in 

 thickness, in number, and in the frequency of their anasto- 

 moses, the blood-vessels which they accompany. The 

 opaque white colour of their contents, and their passage 

 through the mesenteric glands, render their distinction from 



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