1NTE0DUCTI0N. 



5 



ally shown by the ovuliferous scale in Coniferge and 

 the ovnle in the Angiosperms. Celakovsky has fully, 

 clearly, and convincingly pointed out the nature and 

 importance of these phenomena. 



Abnormalities not all Reversions. — That all tera- 

 tological changes are not of the nature of reversions 

 is shown by the change which the structure of flowers 

 undergoes from the pleiomerous to the meiomerous 

 condition, for the former must be regarded as the 

 more primitive, also by the cases of connation and 

 adnation of organs, of the change from a bipinnate to 

 a pinnate leaf or segment, etc. Indeed, the majority 

 of the cases of simplification are "progressive" rather 

 than reversionary ; but it will be noticed that they 

 represent a small minority. Many of these are of 

 great interest as indicating the changes which have 

 already occurred in allied forms along the lines of 

 normal evolutionary development. 



The Value of Abnormalities. — As regards the use 

 and value of abnormalities generally, all botanists 

 have not by any means held the same opinion. For 

 example, members of the Schleiden-Sachs-Goebel 

 school have alw r ays tended to emphasise the facts of 

 ontogeny rather than those of teratology ; indeed, 

 they have largely disparaged a study of the latter as 

 of slight importance. Groebel admits that " in many 

 cases teratology serves as a fingerpost for the right 

 interpretation of morphological questions,"* and that 

 " we are enabled to obtain, by the study of these mal- 

 formations, a deeper insight into the homologies of 

 the organs, and especially those of reproduction of 

 the higher plants. "f 



But he proceeds to state his view that the morpho- 

 logical problems which can be interpreted by means 

 of teratology " are relatively rare and not of out- 

 standing importance." "We must regard the way in 

 which teratology has been developed hitherto as un- 



* Schenk's ' Handbuch.' 

 t ' Science Progress/ 1895. 



