1893. THE RECAPITULATION THEORY. 277 
events not in the position that it first occupies in Antedon. It appears 
from paleontological evidence that this plate first appeared above the 
level of the radials, that it gradually sank down between the two 
posterior radials, and that at a far later period, towards the close of 
the Paleozoic, it gradually passed upwards again, precisely as it does 
in the young Antedon, and eventually disappeared. The ontogenetic 
stages of the anal plate in Antedon are represented in the phylogenetic 
series by Ceriocvinus, Evisocrinus and Stemmatocrinus. Mr. Hurst is 
bound to suppose that such forms as Mevocrinus and Dendrocrinus started 
with an anal plate in a line with the radials, a supposition contrary to 
all available evidence, or that the anal plate in Antedon, together with 
the remarkable changes that it passes through, is a special larval 
development. ‘‘ Mystical” it may be, to suppose that we have here 
an epitome of the ancestral history, but Mr. Hurst can hardly say 
that it is not justified by evidence. 
There are many other curious parallelisms between the growth of 
Antedon and the history of the earlier crinoids. It is, however, 
possible to explain them on Mr. Hurst’s plan, so I merely allude to 
them here to show that they do not in any way run counter to the 
Recapitulation Theory. They are the large size of the basals, the 
peculiar shape of the radials, the well-developed orals, and the 
evolution of pinnules. 
To turn to another passage and to a different group of animals. 
At the bottom of page 197 Mr. Hurst says: ‘‘ In order to produce a 
‘record,’ it is necessary that new chapters be added at the end of the 
pre-existing record. It is necessary that, as the adult structure varies 
in one direction, the late stages of development shall vary in another, 
so as to become, not more like the new adult structure than they were 
before, but more like the old one.” ‘This is hardly a fair statement of 
the case. It is not correct to say that the late stages of development 
must vary in another direction ; for it surely is the case, in any series 
of parents and offspring, which are varying in a given direction, and 
which we may denote At, A2, A3, A", that A® is nearer to A7 than AS 
is. Consequently, if the latest stage of development of the form A7 
resembles A®, it is necessarily more like A7 than a stage which 
resembled As. That is to say, on the Recapitulation Theory, the 
stages of development vary in the same direction as the adults. Mr. 
Hurst’s statement of the method of variation, demanded by the Re- 
capitulation Theory, should, therefore, be amended as follows :—- 
Variation, or change from parent to offspring, takes place by the 
addition of features at the end of the ontogeny ; and these features 
are, by subsequent successive additions, gradually pushed back to 
earlier stages of ontogeny, so that what is the ultimate stage of one 
form is the penultimate of the next, and the ante-penultimate of the 
next after that. 
Although the adherents of the Recapitulation Theory will doubt- 
less accept the above as, in the main, a correct statement of the 
