44 ANNALS OF SCOTTISH NATURAL HISTORY 



and well-defined limits, on a mountain 2 miles east of 

 Arisaig a nameless mountain of an elevation of not more 

 than 1500 feet. Bartholomew's map on a scale of 2 miles 

 to the inch scarcely, or at least doubtfully, indicates it. I 

 applied for information to several of the older inhabitants 

 without eliciting anything definite as to its name. At length 

 the Rev. J. Chisholm, of St. Mary's, Arisaig, a good Gaelic 

 scholar, promised to investigate the matter. In a day or 

 two a card was handed in, on which were written two words, 

 " Sithean Mor." The next step was their pronunciation. 

 An appeal to the Rev. D. M'Lean resulted in words as near 

 the pronunciation as possible, " Shean Mor," with the addition 

 by way of translation, " The larger height of the Fairies." 



The moss second in the order of discovery is Dicrannui 

 Fergussoni. In this instance the specimens show a greater 

 degree of development than those of any other known locality. 

 The more typical show serratures on the upper half of the 

 margin of the leaf, sharply defined, as well as prominent 

 pellucid serratures on the back of the nerve, at times as high 

 as .008 mm. The red tomentum is also, in two instances, 

 as well marked as in D. Miililenbeckii (Sch.), a moss not 

 hitherto detected in Britain ; indeed the whole stems, from 

 base to apex, are shrouded in these felt-like masses. The 

 areolation is besides different from that of D. Scottianniu, 

 inasmuch as the upper cells are oval and much larger, viz. 

 .Oi2-.oi8 by .OO7-.OI mm. Rather abundant throughout 

 the district, but barren. This moss is clearly in process of 

 evolution and differentiation from D. Scottianum, and accord- 

 ingly ought to be closely observed. 



I have now four stations for this moss ; but the speci- 

 mens from Arisaig show a much greater divergence from the 

 original type than those of any of the others. All this implies 

 that I have no belief in the fixity of species ; I mean, of course, 

 in the sense that all freaks and variations on the part of nature 

 quickly revert to the unalterable type, and that there can be 

 no departures from that type such as may lead ultimately 

 to diverse types in the course of time and amid changes 

 of surroundings, etc. All such changes are much more 

 frequently seen in plants of simpler organisations, and 

 especially in genera which propagate, for much the greater 



