28o NATURAL SCIENCE. April. 



stages of its life, and of those that involve unnecessary expenditure, 

 such as a spinous stage in an Ammonite intervening between two 

 costate stages. These explanations of the falsification of the epitome 

 are barely alluded to by Mr. Hurst ; for since, on a priori grounds, he 

 denies any epitome whatsoever, he naturally does not stay to enquire 

 whether he may not have sometimes been misled by these obscura- 

 tions of it. So far, then, as Mr. Hurst is concerned, it is idle to 

 discuss these matters, we must rather seek for flaws in his oiiginal 

 argument. 



His main fallacy appears to me to be simply this, that he substi- 

 tutes contemporary relations for ancestors. After stating Von Baer's 

 law, which obviously refers to existing species, co-existing, that is, 

 and therefore not derived the one from the other, he proceeds to say : 

 - — " If similar comparisons could be instituted between an ancestral 

 species and its much modified descendants, there is no reason for 

 doubting that a similar result would be reached." But there is all 

 the difference in the world between filial and fraternal relationship, 

 and though Von Baer's law is undoubtedly true of the latter, there 

 are many objections to supposing that it is equally true of the former. 

 The only evidence that Mr. Hurst condescends to offer is the quota- 

 tion from Darwin, which is, indeed, one part in favour of himself, but 

 the other six parts in favour of his opponents. 



Mr. Hurst seems to suppose that on the Recapitulation Theory 

 a bird should begin life as a fish, then change to a lizard or other 

 reptile, and finally burst into a bird. Such a harlequinade has never 

 been imagined. The bird of to-day must be compared, not with the 

 reptile of to-day, but with the bird of the past, and that in its turn 

 with a form which may have had very few of the characters of reptiles 

 as we now know them ; as for fish, it is as likely as not that they 

 barely entered into the phylogeny at all. Those who keep a more 

 observant eye on the progress of vertebrate palaeontology than I have 

 leisure to do must surely have observed how day by day the ancestral 

 stocks are pushed further and further back, so that the connecting 

 link between, or common ancestor of, the great divisions cannot 

 possibly be dragged into the discussion. 



To glance at another example of Mr. Hurst's — the three gnats 

 Citlex, Corethra, and Chironomits, forms which, though alike in the adult, 

 are dissimilar in the larval stage. Of course, it is possible that these 

 genera may really be descended from a common ancestor, and that 

 variation has chiefly affected the early stages. If so, it is clearly 

 impossible that those early stages can reveal to us the past history of 

 the genera in question. Such cases as this are admitted by every- 

 one ; they are consistent with the Recapitulation Theory, and as 

 Mr. Hurst makes no further capital out of them, it is hard to see why 

 he introduced them at all. On the other hand, instances are known, 

 as in the Ammonites Dumortieria and Gravimoceras, of adults which 

 resemble one another so closely that they would actually be taken for 



