Il6 THE PERMO-CARBONIFEROUS RED BEDS OF 



be considered only in its application to the few genera, Dimetrodon, Clepsy- 

 drops, Edaphosauriis, and, perhaps, Diplocaulus. They were no more import- 

 ant in the fauna as a whole than Phrynosoma or Basiliscus is in the fauna of 

 the regions in which they live to-day, or than Stegosaurus or Triceratops were 

 in their time and region. It is, perhaps, of some value to test Beecher's 

 theory in these cases. 



I quote several paragraphs selected from his valuable paper, to show the 

 line of his argument, and his conclusions.'' 



Page I : "The presence of spines in various plants and animals is, at times, ob- 

 vious to all mankind, and not unnaturally they have come to be regarded as almost 

 wholly in the light of defensive and offensive weapons. Their origin, too, is com- 

 monly explained as due to the influence of natural selection, resulting in the greater 

 protection enjoyed by spiniferous organisms. But when, upon critical examination, 

 it is seen that some animals are provided with spines which apparently interfere with 

 the preservation of the individual ; that other animals develop spines which can not 

 serve any purpose for protection, or otherwise; and that spines themselves are 

 often degenerate or suppressed organs, then it becomes evident that the spinose 

 condition may have other interpretations than the single one of protection." 



Page 2 : "After studying numerous organisms, the writer is led to believe that 

 in every case no single reason is sufficient to account for their spinose condition. 

 The original cause may not be operative through the entire subsequent phylogeny, 

 so that spines arising from external stimuli, and then serving important defensive 

 purposes, may at a later period practically lose this function ; or spines may become 

 more and more developed, simply by increasing diversity of growth forces, or through 

 the multiplicity of effects. In this way causes may follow, overlap, or even coincide 

 with each other ; but in interpreting special cases, the problems may be quite com- 

 plicated, and often obscure." 



Page 128: "* * * modifications in function and structure are followed by modi- 

 fications in surface, showing that the more important physiological and structural 

 variations are the first to be subjected to heredity and natural selection, which tend 

 to fix or hold them in check. Features of less functional importance, as peripheral 

 characters, are the last to be controlled, and therefore present the greatest diversity, 

 while in this diversity spinosity is the limit of progress." 



Page 266 : "Hypertrophy is also apt to be one result of abundant nutrition, so 

 that structures of little or no use may be developed, and some of them comprise 

 certain features which are often called ornamental." 



Page 332 : "The physiological interpretation of spinosity is a correlative of the 

 morphological aspect of the same condition, and, as it was found that spinosity was 

 a limit to morphological progress or regress, it will now be shown that it also indicates 

 the paracme or decline of physiological progress. Both inferences are drawn from the 

 individual or ontogenetic standpoint, as well as from the radical or phylogenetic." 



Page 353: "It has been shown elsewhere in this article that the greatest develop- 

 ment of spinose organisms occurs just after the culmination of a group, and, as this 

 period clearly represents the beginning of the decUne of the vitality of the group, 

 the spines are to be taken as a visible evidence of this decadence. A similar obser- 

 vation has been made by Packard, who after passing in review the geological develop- 

 ment of the Trilobites, Brachiopods, Ammonites, states that 'these types, as is well 

 known , had their period of rise, culmination, and decline, or extinction, and the 



° Beecher, Amer. Jour. Sci., vol. vii, 1908. 



