Amoeboid cells in intestinal absorption. 27 



Metschnikoft ') (wlio describes the cells as taking in their food after 

 the manner of a Ehizopod) and in the fresli water Medusa (Limno- 

 codium) by Ray-Lankester^). Amongst Turbellarians the direct in- 

 ception of fat globules has been noticed by Graff^) in Vortex Lemani, 

 the amoeboid character of the intestinal epithelium in Plagiostoma by 

 du Plessis-*) and the amoeba-like intus-susception of ingested prey by 

 the epithelium cells by Metschnikoff^). 



But observations of this kind have not been coniined to the 

 lowest Metazoa. In amphioxus and in the cyclostomatous fishes 

 Wiedersheim®) has described a direct inception and digestion of the food 

 by the cells lining the alimentary tract; the passage of the food- 

 particles into the cells being effected by amoeboid protrusions of the 

 cell-protoplasm. And this intracellular digestion is apparently in 

 these animals the only kind of digestion which occurs, for a true 

 digestive secretion appears to be absent in their alimentary cavity. 



It does not appear needful to increase the length of this article 

 by a systematic account of the literature of absorption-, upon which 

 subject, and especially that part which relates to fat-absorption, very 

 numerous memoirs have been written. Those who desire a fairly com- 

 plete bibliography will find it in one or more of the papers which 

 have been referred to, especially in those by Thanhoffer^) and Watney^), 

 and in the article by v. Wittich in Hermann's Handbuch der Phy- 

 siologie, vol. V. 



') Metscbuikolf, Ü. d. intracelluläre Verdauung bei Coelenteraten. Zool. An- 

 zeiger 1880, S. 261. 



^) E. Ray-Lankester, On the intracellular digestion aiid entoderm of Limno- 

 codium, Quart. Journ. of Micr. science, 1881, p. 119. 



^) Graff in Zeitsckr. f. -wissensch. Zoologie, XXV. Suppl. p. 338. 



*) Du Plessis in BuU. d. soc. vaud. d. sc. nat., XIII. 



^) Metscbnikoff, Üb. d. Verdauungsorgane einiger Süsswassertrabellarien. Zool. 

 Anzeiger 1878, S. 387. 



^) Wiedersbeim, loc. cit. 



■') V. Tbanboffer, Beiträge zur Fettresorption. Pflüger's Archiv VIII, 1874. 



^) Watney, The minute anatomy of the alimentary canal. Phil. Trans, vol. 166, 

 part 2, 1876. 



