H. C, DELSMAN. “On the relation of the anus to the blastopore and on the origin of the tail in vertebrates.” 
Fig. 2. Rana esculenta. 
Median section through an egg as in text fig. 16. Fig. 3. Rana esculenta. 
Median section through the egg of text fig. le. 
Fig. 1. Rana esculenta, 
Median section through the egg of text fig. la. 
Fig 5. Amblystoma tigrinum. 
Median section through the egg of text fig. 2a. 
Fig. 7. Amblystoma tigrinum. 
Fig. 4. Rana esculenta. Median section through the egg of text fig. 2d. 
Median section through an egg with closed medullary folds. 
ABBREVIATIONS. 
a. anus, (a) anal pit, a.d. anal diverticulum of gut, arch. 
archenteron, bl. blastopore, can. med. medullary canal, Ap. 
cerebral plate, Lb. liver cove, mes. mesoderm, 7.p. neuropore, 
Fig. 6. Amblystoma tigrinum. (1.p.) place of the future neuropore, p. neur, neurenteric pore, 
Median section through the egg of pl. med. medullary fold, pr. cer. praecerebral thickening of 
Proceedings Royal Acad. Amsterdam. Vol. XIX. text fig. 2b and c. the ectoderm, ventr. mes, ventral mesoderm. 
