QUEKETT MICROSCOPICAL CLUB. 255 



The President said that he was afraid he was not able to 

 throw any light on the significance of the markings and char- 

 acters of the kind Mr. Earland had mentioned. He thought 

 they were quite inexplicable at present. It must be admitted 

 that a great number of specific characters are not due to adapta- 

 tions, and one may go further and ask how far the origin of 

 species is affected by natural selection. What proportion of 

 specific characters are adaptations at all ? How often can one 

 say that any character is really adaptive ? He would like the 

 opinion of some of the Club workers. Would Mr. Rousselet, 

 for instance, say that all the specific characters of rotifers were 

 adaptations ? He would not say an organism w r as not adapted 

 to its environment, but he would say that many organisms 

 exhibit a whole host of characters not due to environment. 

 They could not explain everything as due to natural selection. 

 Darwin laid great stress on " The Origin of Species by Means 

 of Natural Selection," and thought that specific characters came 

 first, and then natural selection came in and weeded out any 

 not suited to the environment. 



Mr. C. F. Rousselet thought it was impossible to determine 

 what characters were really adaptive in the Rotifera. 



Mr. D. Bryce said natural selection did not apply to his 

 Bdelloids, as they were all females. It was a real case of sur- 

 vival of the fittest. Occasionally a specific character must be 

 an absolute hindrance, and, in the case of long spines, must 

 sometimes be positively dangerous. 



The President said it was very difficult to put oneself in the 

 position of, for instance, a sponge. But take the case, say, of a 

 small protuberance on a spicule, which spicule is quite sur- 

 rounded and embedded in the general protoplasmic mass of the 

 animal, and then assume another similar spicule which is without 

 such protuberance. It is not possible to conceive that either 

 the presence or absence of such a minute speck of silica could 

 be of any use to the individual, and yet such a difference is often 

 absolutely characteristic of a species. We have had instanced 

 this evening elaborate decoration and markings on Foraminifera. 

 These animals certainly cannot appreciate them visually, as they 

 have no organs of vision ; and, again, in life the markings would 

 be concealed under the usual gelatinous mass of exterior proto- 

 plasm. The markings are so minute that it is quite impossible 



