274 



GEO. S. HUNTINGTON 



t ^ ® 



6 



Figure 4 



Figure 5 



1, Precardinal vein 1, Precardinal vein 



2, Dorso-medial somatic tributary 2, Dorso-medial somatic tributary 



3, Perivenous mesenchymal syncytium 4, Mesenchymal blood-islands 



