Next Pander referred to the galoons, the white concentric 

 spheres bordering the cicatrice. In a footnote he indicated 

 that until now nobody could explain their structure. 

 Especially Oken, in his "Manual of the Natural History," said 

 that he did not know their nature, and suggested their con- 

 nection with the vascular system. This suggestion Pander 

 considered devoid of basis. He himself distinguished two 

 types of galoons, one related to the blastoderm, which exists 

 even before the incubation, and another which appears on the 

 second and third day and develops in the yolk itself; the 

 most external of these corresponds with the border of the 

 blastoderm, 9 



Until the sixteenth hour of incubation (§ 4) the trans- 

 parent area has an elongated pear-shaped form. In it are two 

 opaque parallel lines, which in Pander's opinion are the folds 

 forming the blastoderm in the direction of the shell (Drawing 23, 

 1 - 2) . "These first traces of the developing embryo are 

 called the primary folds, and what is found between them we, 

 with Malpighi, call the intermediate careen," 20 (71). 



In one part of the transparent area the primary folds 

 very early turn up to the center and join each other in an 

 arch; and in the opposite area they, on the contrary, become 

 separated. Until this takes place, the transparent area 

 gradually changes its shape from pear-shaped into biscuit-form 

 (Blumenbach) or, Pander suggested, they acquire the shape of 

 sandals. Between the primary folds, Pander saw a quickly 

 developing delicate whitish filament, which he considered the 

 spinal cord. The spinal cord turns into the brain. The 

 opaque area is divided into two zones: the internal repeats 

 the sandal shapes of the transparent area, and the external 

 zone has an elliptical form. The nucleus of the embryonic 

 disk swells, is easily separated from the yolk, and then 

 below it a pit is observed. 



In the twentieth hour, embryos (§ 5) are "composed of 

 primary folds and spinal cord, which develop from the blasto- 

 derm and in an unknown way are connected with the place of 

 formation," according to Pander. He distinguished two 

 ends — the upper, or the head end, where the folds coincide, 



19. The term galoon is not employed in later embryological 

 literature, because the rings designated by it are not 

 permanent formations. 



20. Pander, DISSERTATIO, pp. 28-30. 



251 



