486 REIGHARD—PHELPS. [Von scies 
section — they are not visible from the exterior — of hav- 
ing been flattened dorso-ventrally so that the two limbs of 
either curved row of cups lie parallel to one another and close 
together. The four ends of the two rows are thus brought 
together and the four median cups (lying at the ends of the 
rows) are in contact with one another. ‘These four cups open 
Fic. G.—Longitudinal (sagittal) section of the tip of the upper jaw of an 
18 mm. larva of Amia, showing the adhesive organ in a late stage of 
degeneration. Camera outline drawing, about 170. adh. org., ad- 
hesive organ; ect., ectoderm; 1. 1. org., lateral line canal; mes., 
mesenchyme; pg. c., pigment cell. s. b., sense bud; s. mx., cartilage 
of the upper jaw. 
to the exterior through a common aperture, the median open- 
ing spoken of above, while the remaining cups no longer com- 
municate with the exterior. 
The cups have lost their original spherical shape and there 
is a tendency for them to open into each other. The degen- 
eration of the organ appears to have begun at the sides and 
to have proceeded toward the median plane. The boundaries 
of the organ are still perfectly definite and the cells have the 
