PLATE 3 



EXPLANATION' OF FIGURES 



27. 28, 29, and 30 X 120. Wax reconstruction of a segment taken from the 

 middle of the digitiform gland, showing tubule formation in Acanthias embryos. 



27 Embryo 28. 1 mm. in length. 



28 Embryo 33.1 mm. in length. 



29 Embryo 47.5 mm. in length. 



30 Embryo 95 mm. in length. In figure 30 only a small portion of the wall 

 of the gland is shown. 



366 



