3698 The Zoologist — September, 1873. 



the very commendable fashion that has set in. The pubUc are becoming 

 every day better acquainted with the pecuharities of the more recondite 

 creatures who hve where the purple mullet and the gold fish rove, and 

 where the mermaid is decking her green hair with shells — creatures, many 

 of them, which were not nearly so well known before this to most people as 

 the mermaid herself." — ' Daily News,' August 18. 



[This neat but comprehensive paragraph appears in a leader, not as an 

 advertisement. — E. N.] 



A Difficulty for Darwinists (see Zool. S. S. 3581 and 3654).~I have 

 read the objections to my paper, quoted from ' Nature,' in your last number, 

 and avail myself of your kind offer of space for replying to them. I quite 

 agree with the writer of the criticism that the title, " A Difficulty for Dar- 

 winists," was objectionable as being pretentious ; the difficulty, however, was 

 one which occurred to my own observation, and wliich has ever since 

 remained as a bond fide difficulty to the acceptance of Darwin's theory, in 

 my own mind. I am quite willing to admit that I do not fully understand 

 the subject. I do not pretend to anything more than a smattering of 

 Zoology ; still the remarks in ' Nature ' do not seem to me a satisfactory 

 solution of the matter ; so far as I can understand them they are more like 

 a cursory opinion, not meant for serious consideration, than really addressed 

 to the difficulty. If I have not adverted in my paper to the possibility of 

 such an answer being made it was because it hardly seemed necessary. The 

 writer concedes to me that " it is theoretically possible for an infinite 

 number of variations to occur in living bodies," as if my argument had been 

 all about abstract possibilities, and then takes up a position to show from 

 actual fact what was probable and what was not. Now this is a position 

 I cannot yield to him. I had already stated it as afact that the forms and 

 arrangements of teeth in vertebrates wei'e practically infinite, and that the 

 structure and development of teeth in the wombat, thylacine, dog and rodent 

 respectively, were exceedingly complicated and high types of development, 

 there being evidence to show that the steps in their evolution have been 

 exceedingly numerous and gradual. It will not do for my criticiser to 

 assume that I have only argued in an abstract way that " It is possible for 

 an infinite number of variations to occur in living bodies." If he wishes to 

 attack this position of mine he must first show that my statement of fact is 

 wrong, i. e. that there are but few forms and arrangements of teeth in nature, 

 and that those of the wombat, thylacine, dog and rodent, are organs of low 

 type and simple development. The writer goes on to say that marsupial 

 and placental types of organism having had " to undergo the struggle for 

 existence under similar circumstances, it is not to be wondered at, but only 

 to be expected, that similar organisms should be the result." Now I do 

 not think any genuine Darwinist would accept this sentence as a sound 



