660 



BASHFOED DEAN, 



tbe yolk mass is seen to be closely apposed to the hindmost part of 

 the gullet, enclosed in fact within its peritoneal investment; it has 

 become broken into lobes, frora whose translucent, periblastic margins 

 the vitelline capillaries, nutriment laden, are passing liverward, unit- 

 ing and enlarging tili they become tbe vitello-intestinal veins, V. 

 Hindward of tbis region the yolk mass has increased somewhat in 

 size, but retained its intimate relation witb tbe gut; in Fig. M, a 

 transverse section tbrough tbe bind gut, tbese conditions are illustrated ; 

 the yolk mass, Z, lies as before morphologically within the side wall 

 of tbe gut, enclosed by its peritoneal sheathing ; its substance is 

 broken into lobes, along whose margins on the side of the gut the 

 blood vessels are converging liverward, — these blood vessels in 



M. 



Figs. L, M. Transverse sections of visceral region of larva of seven days. Fig. L 

 through the gullet. Fig. M through the intestine. AB Air bladder, BC body cavity, 

 G gullet, / intestine, L Liver, P periblast zone of the yolk, Y yolk. 



turn arise in the vitelline capillaries which furrow the yolk Seg- 

 ments and draw their nutriment from the yolk's peripheral zones 

 (mainly from the sides away from tbe gut). It will thus be seen 

 that the yolk-nutriment supply of Ämia reaches the liver through 

 vitelline veins which pass between the yolk mass and the gut; accord- 

 ingly it follows that the conditions in Serranus would be attained 

 without Wide caenogenetic changes; for tbe growth of the liver oc- 

 curring in Teleosts more precociously, could naturally cause the 

 shortening of the length of the vessels connecting it witb the yolk; 

 by tbis process the liver would early become attached to the yolk 

 and receive its vascular supply from the capillaries directly: tbese, 

 shortened in turn by still more precocious devclopment, would, it is 

 evident, ultimately be replaced by the growing tissue of the liver — 



