133 



indicate ? Surely they teU us plainly of what we have 

 already so often insisted upon^ — namely, the redun- 

 dancy of this once continuous land with specific foci of 

 its own, and the sluggish or sedentary nature of those 

 primoeval radiating forms. 



We must not however omit to notice, that some few 

 of these endemic Helices appear to have been gifted (as 

 we should a priori anticipate) with more rapid capabi- 

 lities for difiPusion than the rest. Thus, the H. erubescens 

 and paupercula seem not only to have colonized the 

 entire province of which the Madeiras are detached frag- 

 ments, but to have even found their way to that distant 

 portion of it which now constitutes the Azores. The 

 H. polymorpha has also penetrated the Madeiran region 

 throughout ; and being, like the H. erubescens, peculiarly 

 sensitive to the action of external influences, we per- 

 ceive, in consequence, that almost every island and rock 

 has now its own especial phasis of it. So greatly indeed 

 is that species beneath the control of local circum- 

 stances, that the very districts of an island as insignifi- 

 cant as Porto Santo have each their separate races to 

 boast of. On the Pico d'Anna Ferreira it assumes a 

 form to which the name of H. attrita has been apphed ; 

 when on the Ilheo de Baiso, it is the H. papilio ; at the 

 Zimbra d'Areia, on the Pico de Conseilho, and in the 

 Ribeira da Coxinha, it is the H. pulvinata; and, in 

 many other situations widely removed inter se, it puts 

 on the shape (variable, both in size and hue) to which 

 the title of H. discina has been given. But, if we leave 



