THESIS ON THE BRACHIOPODA 181 



have given a fair account of at least ninety-five per cent of the 

 species which had been described, and tabulated the synonymy 

 reasonably well. I dissected representations of recent species, 

 and did like work with some twenty species of fossil forms, by 

 slicing specimens on the lathe and treating with acids. 



My thesis was concerning the Brachiopoda in general, with a 

 special study of the bilaterality of the group. It was an argu- 

 ment against the Darwinian hypothesis based on the develop- 

 ment of the second series, in which I endeavored in the first 

 place to show that several of the series develop at great organic 

 cost and in a well-ordered succession of changes, features which 

 not only cannot have any utility, but which are apparently 

 disadvantageous, as for instance the proboscis like exten- 

 sions of the margins of the shells in Producta, the exogenation 

 of the mixed folds in Orthis biloba, the ridges and knees of 

 Leptina, etc. Then I discussed the development of the lateral 

 symmetry particularly in the spirifers and Rhynchonella, en- 

 deavoring to show that the lateral balance of the calcified fur- 

 rows of the so-called arms could not have been brought about 

 by selection, but must have been the result of some other sym- 

 metry-determining influence. Incidentally, I tried to prove 

 that the longitudinal axis of the brachiopod did not lie in the 

 plane of function of the valves, but extended from the centre 

 of one to the centre of the other, at right angles to both. I have 

 not seen this thesis since it was delivered to the examiners, but 

 as I recall it, it was a worthy piece of work, creditable to the 

 teaching I had received. It contained some points which 

 pleased Agassiz greatly, especially the study of symmetries. 

 He did not like my treatment of the Darwinian hypothesis, for 

 I did not scout it, but claimed that, while its general value was 

 uncertain, it clearly could not account for a considerable array 

 of facts, natural selection in a word could not explain the 

 development of the group ; there was a suspicion of heresy in 

 the way the matter was treated. 



That work such as I did in the Museum could be done at all, 



