4 NOTES AND COMMENTS [january 



Quoy, who reviewed the parts as they appeared in the Bulletin des 

 Sciences Naturelles, says in one of his notices that the authors had 

 abstained from giving any text to the first twenty parts for fear of 

 increasing the price of the book, and above all from their delicacy of 

 writing after the illustrious Buffon. They were, however, compelled 

 to do so because the foreign Customs rejected a collection of plates 

 without text, considering them as the product of the arts of France 

 rather than as a scientific work destined to be circulated all over 

 Europe. This was in 1824. Times have changed since then, but 

 we can recall an instance of stupidity on the part of British Customs 

 officials even within the past decade, connected with a book on " Greek 

 Vases." . , 



A Thorny Subject. 



Mr. C. E. Beecher has published an interesting study on the " Origin 

 of Spines " (Am. Journ. Sci. 1898, vi. pp. 1-20, 125-136, 249-268, 329- 

 359, 73 figs.). He points out that the suggestion of protective 

 function, so freely made, is not always valid ; but although the elimina- 

 tion value of spines and related structures may be slight, yet the 

 spinose condition itself can, he says, be shown to be of much import- 

 ance. " It represents a stage of evolution, a degree of differentiation 

 in the organism, a ratio of its adaptability to the environment, a result 

 of selective forces, and a measure of vital power." 



Mr. Beecher emphasizes the fact that spines or equivalent structures 

 are rarely present in young forms, but appear during the process of 

 growth, and he seeks to distinguish two types of spine-development. 

 One type, well exemplified in the Barberry, shows that spines may 

 develop from the degeneration of organs, as in plants from leaves, in 

 animals from appendages, e.g. the spurs of the python, and so on. In 

 the other, the ornamental type, well seen in the shell of Spondyhis, the 

 spines do not arise from a check to growth, but from an excessive 

 development of functional parts. Further, just as in ontogeny spines 

 of both types develop late, so phylogeny proves that spinose or orna- 

 mented forms have behind them a long history of simple unadorned 

 ancestors. This is well seen in Spondyliis itself, which is descended 

 from forms with simple smooth shells ; in many Brachiopods, which 

 became spinose just before extinction ; in the history of the whole 

 phylum of Echinoderma, whose members have become increasingly 

 spinose in geological time. Phylogenetic studies of this kind show 

 also that the " maximum of generic, family, and ordinal differentiation 

 is found at an early period, while the greatest specific differentiation 

 occurs at a later period." That is, variation first affects physiological 

 and internal structures, while later the changes are mainly physical 

 and peripheral. In other words, in any developing group " the more 

 important physiological and structural variations are the first to be 

 subjected to heredity and natural selection, which tend to fix or hold 



