EFFECTS ON THE HIGHER INVERTEBRATES 



45 



baum and Oxner. Oxner ('n) reported briefly the results in Lineus ruber and 

 Linens lacteus. On decapitation of young fasting individuals (or of older ones 

 just after extrusion of the sexual products), the body undergoes a process of 

 reduction and involution, without sexual maturation. If the sexual system has 

 reached a certain stage of maturity, however, it will continue independent develop- 

 ment to maturity in spite of the decapitation with consequent inanition, which 

 prevents further growth of the body in general. 



The changes in Lineus ruber and Lineus lacteus were studied in detail by 

 Nusbaum and Oxner ('12). The starvation was in sea- water for various periods, 

 six to thirteen and one-half months. The external dimensions of Lineus ruber 

 reduced to }■■■§ or x %, all parts being nearly proportionately reduced (thus differ- 



ng.0 



Fi G I5 — a magnified portion of a cross section of the nemertin worm, Lineus ruber, after 

 starvation for I2 1 A months. (From Nusbaum and Oxner '12.) Surface epithelial cells (ep) 

 are markedly reduced in size. Stroma ("parenchyma") cells (St) of the underlying connective 

 tissue are more closely packed, due to loss of the interstitial gelatinous substance. Muscle 

 fibers (Mf) are greatly atrophied. Pigmented tissue (originally abundant) has largely dis- 

 appeared from the body wall, being transported by phagocytic wandering cells (Pc) to the 

 intestinal wall (7m) serving as food for the starving organism. Areas- of intestinal epithelium 

 also undergo pigmentary degeneration into syncytial areas (So) which are finally absorbed. 



ing from the planarians). In Lineus lacteus, however, the posterior portion is 

 more reduced. The body wall is normally 0.06 to 0.09 mm. thick; including 

 0.02 mm. for cutaneous epithelium, 0.025 mm. for the "parenchyma" (stroma) 

 and outer muscle layer, the remainder being the middle and inner muscle with 



