No. 3.] LATERAL LINE OF AMIA. 503 
actual sections. In Cut 4 is seen the cord along which the 
organs lie, and an organ developing in it. The organ at this 
Cut s. Cut 6. 
Cut 4.— Longitudinal section through a line of pit organs in a fish 45 millimetres 
long, showing four organs, one of which is just forming, all connected by a cord of 
cells in the deeper layers of the epidermis. 
Cut 5.— Longitudinal section through a line of pit organs in the adult, showing 
three organs and the connecting cord. 
Cut 6.— Section through a developing organ of the suborbital line in a fish 114 
millimetres long, showing large vacuolar space at top of organ. 
Cut 7,—Thesameina fish millimetres long, where the organ has reached the 
other surface. 
Cut 8.—The same ina fish millimetres long, where the organ is beginning to 
sink below the surface and the osseous canal is forming. 
Cut 9.—The same in a fish millimetres long, where the canal is just closing 
over the organ, showing the nearly formed osseous canal and the nerve leading 
through it to the organ. 
