No. 3.] LATERAL LINE OF AMIA. 467 
to a line of pores usually somewhat curved, and to a canal of 
the form shown in Cut 1, g. The division of the terminal pores 
of such a line may then proceed more rapidly than that of the in- 
termediate ones, thus producing creeper-like canals of the form 
shown in /; or later, divisions may take place at an angle to 
the original direction of division as shown in z, the angle being 
usually a right one, or nearly so, and then again in the same 
direction, or in the original direction, thus giving rise to a series 
of intersecting, or parallel lines, and to a more or less compli- 
cated arrangement of pores in groups of different sizes and 
shapes. There is in this process of multiplication a strong ten- 
dency to keep the pores of the different lines and groups at 
BERR OO 
Bee 
g h ) 
CuERT. 
Cut 1.— Diagrammatic representation of the formation and subsequent division 
of a primary pore or tube: a, 4 and ¢, two half-pores approaching each other and 
fusing; d@, primary pore and tube; ¢, the same, undergoing its first division, which in 
f is completed; g, dentritic system after second regular division; 4 and 2, forms of 
creeper-like branches. 
about the same distance apart, so that when the groups become 
large, somewhat geometrical designs are formed, and any particu- 
lar pore may appear to belong to one of two or more intersecting 
surface lines, either one of which might be taken, from surface 
indications alone, to be the line of formation of the series. 
This is the regular method of multiplication and formation of 
the pores and branch canals in Amia, none of them being formed 
by growth from beneath; that is, by the canals first forming 
there as diverticula, or prolongations of existing canals, and 
then forcing their way through to the upper surface. Not a 
