144 NATURAL SCIENCE. Aug.. 



knowledge of ontogenetic and septal details in both cases ! If a 

 schoolboy were to class a whale as a fish, Professor Blake would be 

 down on him for his ignorance ; but the blunder in a schoolboy would 

 be more excusable than are such remarks about Ammonites from 

 Professor Blake. 



We have given so much time to the criticisms of these various 

 matters, that we cannot allude to numerous statements in this extra- 

 ordinary paper ; but we must not pass the cream of the whole article. 

 " By comparing the figures [in the plate] ... we seem to see how 

 the Stephanocerata (pi. i., fig. ii) may have arisen from Hammatoceras 

 (pi. i., fig. lo) ; and by comparing this with pi. ix., fig. i, of Vacek's 

 work almost from Havpocems. In another direction we can pass 

 towards Pevisphindes (pi. i., fig. 13), and in a third towards Aspidoceras 

 (pl.i., fig. 12), and there is little to distinguish them in the outlines " ! 

 What skill and study must have been expended to construct such a 

 complicated genealogy as this ! We venture to say this effort has 

 never been surpassed, not even by a would-be populariser of 

 Science. 



The Stephanocerata (pi. i., fig. 11) — an inflated shell with a spinous 

 centre and costate outer whorl — " may have arisen from Hammaioceras 

 (pi. i., fig. 10) "which is a cowi/^'^ss^i, wholly costate form, and has 

 not the ghost of a spine about it, apparently ; and this, " almost 

 from Harpoceras" (Vacek, ix., i) a less compressed fossil with a smaller 

 umbilicus — evolute in youth but more involute with age ! "In 

 another direction we can pass towards Perisphmctes (pi. i., fig. 13)" 

 — by a species which has remarkable and very distinct septa, namely, 

 a peculiarly abbreviated siphonal lobe, and a lateral lobe specialised 

 for a very particular purpose — features altogether unknown in 

 Perisphinctes. " And in a third towards Aspidoceras (pi. i., fig. 12)" — 

 except for septal details. 



Of ontogeny Professor Blake takes not the smallest account. 

 He writes a paper on the bases of the classification of Ammonites, and 

 never so much as mentions ontogeny, except to admit the similarity 

 of ontogeny to phylogeny as a guide in genealogy. Does Professor 

 Blake know what these words mean ? and has he applied to this 

 genealogy a principle which he has utterly ignored in his paper ? 

 According to this genealogy, the facts of evolution are not given 

 clearly enough nowadays ; and we have always applied them the 

 wrong way about. Obviously, we have to learn that the details of 

 embryology show whither a species is going, and the details of 

 senility which illustrate whence a species has come ! 



We are indeed grateful to Professor Blake and his genealogical 

 table for giving us such information as this, and for showing us how 

 to use it. We shall be able to correct the misapprehensions in regard 

 to evolution under which we have hitherto laboured. For the future 

 we can construct a genealogy like this : — Here is a monkey who grows 

 less hairy in his old age — he shows how monkeys may have come 



