We may mention, too, as showing clear marks of the influence of transcendental ideas, L. Agassiz's work on the principles of classification.[316] And Serres, who was Geoffroy's chief disciple, recanted not a whit of his doctrine of recapitulation, but re-affirmed and expanded it from time to time, and particularly in a lengthy memoir published in 1860.[317] But in general we may say that pure morphology in the Geoffroyan or Okenian sense was becoming gradually discredited. A curious indication of this is seen in the fact that not only the idea but the very word "Archetype" came to be regarded with suspicion. Thus even J. V. Carus, who had much affinity with the transcendentalists, wrote of the vertebrate archetype (which he took over almost bodily from Owen)--"It may here be observed that this schema may be used as a methodological help, but it is not to be placed in the foreground" (_loc. cit._, p. 395). Huxley, who was definitely a follower of von Baer, was much more outspoken with regard to ideal types. In an important memoir on the general anatomy of the Gastropoda and Cephalopoda,[318] he set himself the task of reducing all their complex forms to one type. In summing up, he writes:--"From all that has been stated, I think that it is now possible to form a notion of the archetype of the Cephalous Mollusca, and I beg it to be understood that in using this term, I make no reference to any real or imaginary 'ideas' upon which animal forms are modelled. All that I mean is the conception of a form embodying the most general propositions that can be affirmed respecting the Cephalous Mollusca, standing in the same relation to them as the diagram to a geometrical theorem, and like it, at once imaginary and true" (i., p. 176). Again, in his Croonian lecture on the theory of the vertebrate skull, he remarks that a general diagram of the skull could easily be given. "There is no harm," he continues, "in calling such a convenient diagram the 'Archetype' of the skull, but I prefer to avoid a word whose connotation is so fundamentally opposed to the spirit of modern science" (_Sci. Memoirs_, vol. i., p. 571).