324 ORR. ' [Vol. I. 



end of the heart, the liver and pancreas make their first appear- 

 ance. They grow out toward the right side of the embryo as 

 hollow diverticula of the intestine ; and are almost opposite each 

 other, the liver tending ventrally and the pancreas dorsally (Fig. 

 40, C, PI. XV.). The liver is the first to assume a glandular ap- 

 pearance. It projects into the venal sinus, behind the heart, so 

 that its relations to the circulatory system are about the same as 

 those described by Shipley^ in Petromyzon. 



In Anolis, although the walls of the neurenteric canal appear 

 distinct in my youngest stage, yet the lumen makes its appear- 

 ance at a rather late period. The alimentary canal extends a 

 very short space behind the allantoic diverticulum, and then 

 bending upward, its lumen becomes that of the neurenteric canal. 

 This region presents the usual features of the fusion of the three 

 germ-layers. Ventrally, just behind the allantois there exists in 

 an early stage a median elongated thickening of the epiblast. 

 A solid mass of cells extending from the intestine is fused with 

 this thickening anteriorly. This is the spot where the cloaca 

 appears later ; and, in view of the recent researches on the sub- 

 ject, I should judge it to be the last trace of the blastopore. 

 The neurenteric canal remains open a comparatively long time. 

 There is still a trace of it in embryos in which the tail extends 

 behind the cloaca more than half the length of the trunk. Fig. 

 58, PI. XV., represents a section through the tip of the tail of 

 such an embryo. The section seems to be not exactly trans- 

 verse. In the centre is seen the neurenteric canal (^NeC) ; at 

 the right are a few cells of mesoblast ; and at the left a fused 

 mass of mesoblast and hypoblast {MHp). Above the latter, 

 and next to the ectoderm, is a small round body {N), which, 

 when followed forward, approaches a central position, and is 

 found to be the notochord. This appearance is very peculiar, 

 and seems to indicate a very irregular and rudimentary condi- 

 tion. I have examined this part in only a few embryos at this 

 stage, but found no two exactly alike. - A little farther from 

 the tip of the tail (Fig. 57) the medulla {Md), notochord (TV), 

 and caudal intestine {AL) become well defined. The caudal 

 intestine sometimes shows a lumen, and sometimes is only a 

 cord of cells, though with indications of a lumen. The meso- 



^ Shipley. — On some Points in the Development of Petromyzon Fluviatiiis. — Quart. 

 Jour, of Mic. Sci., Jan., 1887. 



