312 
E. W. MACBEIDE. 
Part II. 
Comparison op the Process op the Formation of the 
Layers in Amphioxus with the same Process in the 
Higher Vertebrata. 
Before entering' on a comparison of the formation of the 
layers in Amphioxus with the same process amongst the 
higher Vertebrata, it is necessary to discuss the position of 
Amphioxus amongst the Vertebrata. Hubrecht, and some 
others with him, have argued that Amphioxus is not a 
primitive but a degenerate form, and hence that its develop- 
ment must be disregarded, for this would prove exceedingly 
inconvenient for their theories. Now it must be admitted 
that in some points Amphioxus is degenerate, and, as we 
have seen, its degeneration may be brought into connection 
with its burrowing habits in which it has diverged from the 
life of its class. But the same is true of all the primitive forms 
which Nature has kindly preserved for our inspection, except 
those few, like the Sphenodon of New Zealand, which 
are confined to very restricted and sheltered areas. All wide- 
spread primitive forms must be degenerate, for how could a 
primitive animal, whilst retaining its ancestral habits, main- 
tain itself in competition with the improved races which have 
sprung from its stock ? The thing is absurd ; such an animal 
can only maintain itself by getting out of the way, and taking 
to a secluded mode of life. Moreover, if Amphioxus is 
objected to on this ground, an equal objection must be sus- 
tained against Peripatus, against Chiton and the Amphi- 
neura amongst Mollusca, against Limulus amongst Arach- 
nida, against, in fact, every animal that has thrown any light 
on the primitive structure of the class to which it belongs. 
All woi’kers in vertebrate morphology, when they have to 
deal with the evolution of particular organs, descend to 
Amphioxus; and why should we not have recourse to this 
foi-m when we seek to give an account of the formation 
