PLATE 4 



EXPLANATION OF FIGURES 



8 Stellate connective tissue cells exhibiting locomotion and, on contact, appar- 

 ent fusion. /, from the pectoral fin of a 10 mm. Fundulus embryo. The fusion 

 between cells a and b is apparent only, b and c appear to form part of the anas- 

 tomosing syncytium. 77, from the caudal fin of a 6 mm. Fundulus embryo. Cells 

 e and g on coming into contact at 4.44 p.m. apparently fused after the manner of the 

 cells which form the delicate early connective tissue syncytium. Letters and 

 numerals as in the preceding figures. 



9 Stellate connective tissue cells in the subectodermal mesenchymal syncy- 

 tium of a 25 mm. embryo pig. Fibrils pass through the cells very close to the 

 nucleus. Bielschowsky stain. 



10 Connective tissue cells from the prevertebral (I) and intermuscular (II) 

 connective tissue of a 100 mm. pig embryo. The forrn of the cells and their 

 contact relations to adjacent connective tissue and muscle fibers is strikingly simi- 

 lar to the amoeboid connective tissue cells of the living fish embryo. The appear- 

 ance suggests that such cells were quite probably moving along the surfaces with 

 which they are in contact. 



148 



