ZOOLOGICAL NOTES 181 



(Dicks.), to the general appearance of which it bears a considerable 

 resemblance. 



PTEROGONIUM GRACILE, var. PUNCTELLUM. In all, or nearly all, 

 the numerous specimens of this moss that have been gathered, more 

 especially in the West of Scotland, large pellucid papillae have been 

 discovered on the back of the leaf, visible even in the field by the 

 aid of a Coddington lens. These papillae are situated especially along 

 the track of the nerve, but are also seen scattered over the rest of 

 the leaf. They are pellucid, bluntish, incline somewhat forwards 

 towards the apex of the leaf in the manner of serratures, and vary in 

 height from 4 to 8. As I have not detected these papillae on the 

 specimens I possess from Professor Schimper, nor on the single 

 specimen from Cornwall, while works on the subject I have seen 

 speak of the back as smooth and shining, I have determined to 

 separate the Scottish moss from the rest. As I cannot, however, 

 satisfy myself that there is sufficient evidence in other directions to 

 warrant a separation of this as a species from the other, I have con- 

 stituted it a variety as given above. 



Similarly, I have detected on nearly all Scottish specimens of 

 Hypnum crassinervium a nodule on the back of the leaf correspond- 

 ing to that seen in a similar situation in H. illecebrum ; and what is 

 more, this nodule is seen much more frequently in the former than 

 in the several specimens I possess of the latter. At times two such 

 nodules may be detected in close proximity. 



It may be as well, meanwhile, to give expression to this 

 peculiarity, not hitherto noticed, by calling this variety noduliferum. 



GLASGOW, \a,th April 1900. 



ZOOLOGICAL NOTES. 



The Black Rat in Orkney. Mr. Angus Buchanan of Paisley, an 

 Orcadian, has received a Black Rat (Mus rattits), or " Blue Rat " as 

 it is popularly known in the islands, from South Ronaldshay, and has 

 presented the specimen to the Paisley Museum. This example is a 

 female, is 7.5 ins. in length and weighed 7 oz. 8 drs., and is thus 

 above the average in size. The description of the colour of this 

 species in Bell's " British Quadrupeds " appears to me to be based 

 upon English specimens, while Scottish specimens have not been 

 examined a very common thing in natural history works. The 

 description of this Orkney specimen is as follows : The fur long, 

 shorter on the forehead ; the colour of the head and back slate 

 black, on the back mixed with long white hairs ; the hairs on the 

 back darker at their tips, and leaden or slate coloured towards their 



