OF planocera elliptica. 
21 
I scarcely need allude to figs. 81 and 82, a as illustrating the permanent activity of 
the embryonic substance, for they show the same process of cellular life as in fig. 54. 
The proportional size and the degree of development alone differing, hence more im- 
portant in other respects. 
The substance, in the larval state, is still more heterogeneous than in the embryo, 
and continues to be such ; there is no return towards that uniform structure of the vi- 
tellus as observed during its formation, and before and after its division. The future 
labor of the organism is diversification. 
The substance, in the chrvsalis state, I have not been able to examine thoroughly. 
XII. 
THE LARVA. 
The larva retains the plastic nature and assumes the polymorphic outlines which 
we have noticed in the embryo. The preponderant forms assumed are already fore- 
shadowed some time before the latter breaks its outer envelope (fig. 84 — 91). It still 
moves with all degrees of velocity, mayhap more rapidly, being now free from all 
obstacles and allotted to steer in almost any direction which opens itself before it. 
The forms, however, of the larva are not quite as diversified as were those of the 
embryo. Its plasticity is more of a temporary character, affecting rather the regions 
one after another, than the general outline itself. 
A few days after their breaking out of the egg, the larvse appear under two typic 
shapes. In one the back or middle upper region is concave, whilst both extremities 
are somewhat elevated; it has a camel-like outline (fig. 94). In the other, the back 
is convex, very elevated and both extremities declivous ; the outline is dromedary-like 
(fig. 99). In both forms the sides are rounded, and the anterior region is much nar- 
rower than the posterior one, as exhibited by the figs. 95 — 98 and 100 — 103. The 
under part of the body does not differ otherwise from its appearance in the embryo, 
except that the grooves are deeper, and consequently rendering the hillock-like eleva- 
tions more prominent, making the animal to appear as if supported by three pillars or 
columns (figs. 96 and 103). In both forms also, cases may occur, which are al- 
ready to be observed, though but slightly indicated in the embryo, in which the an- 
terior region is divided, causing four of these pillars or processes to be present. Figures 
of these were not deemed necessary; fig. 85 conveying a correct idea of the fact here 
alluded to. When such, however, happens to be the case, the anterior region is as 
broad as the posterior one. 
The rapid motion of the larvse, prevented my seeing them either at rest or even 
permanently, in the focus of the microscope ; their small size requiring a high 
magnifying power, reduced considerably the field of vision. Attempts at fixing 
