Huxley was piecing together the scattered fragments, and
gradually learning to see here and there whole branches, as yet
separate at their lower ends, but in themselves shapely, and showing a
general resemblance to one another in the gradual progression from
simple to complex. The greatest of these branches that he had pieced
together was the group of Medusae and their allies, now known as
Coelenterates. He had formed similar branches for the Molluscs and
minor branches for the Salps and Ascidians, and, in his general
lectures on the whole animal kingdom, he had shadowed out the broad
arrangement of the main divisions, or, as he called them, _types_. He
had seen in each particular branch the clearest evidence of the laws
of growth which had directed its development, and had realised that
these laws of growth, consisting of gradual modifications of common
typical structures, were identical in the different branches. He had
taken clear hold of Von Baer's conception that the younger stages of
different types were more alike than the adult stages, and here and
there he had made comparisons between the younger stages or simplest
forms of his different branches, and had shown that, without
completely realising it, he was ready for the idea that just as the
separate pieces could be arranged to form orderly branches, so the
separate branches might come to be arranged as a single tree.
Pages:
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153