40 



origin of a new species, or variety of a species, in the genus. I have 

 made inquiries about the locality \vhere these animals were found, 

 as to whether others had ever been observed tliere before they were 

 discovered, or have been met w'ith since, and find these to have been 

 the only known instances of their occurrence. 



I am not a\vare that in the nests of the Rook, Corvus frugilegus, 

 or the Black-bird, Merula vuJgaris (whieh I mention as being those 

 in w]iose productions lusus naturce are the niost freąuently noticed), 

 or in the nests of any other bird, more than one individual of a 

 brood has been found, constituted in the healthy condition, and 

 ha\-ing the plumage vvhite, and the red eye of the true albino ; but 

 variations in colour, &c., may occur in any number, as the resnlts of 

 physical impediments, and not natūrai production ; however, \vith 

 iucrease of strength and health, these generally obtain afterwards 

 their proper-coloured plumage, and are not therefore true lusus 

 naturce. To quadrupeds I believe the rule eąually applies. 



In couseąuence of the interesting conversatiou which followed the 

 reading of the foregoing paper, 1 think it proper to subjoin a few 

 other observations. 



The excellent condition and clean appearance of the animals, and 

 their well feeding, and activity, left no doubt as to their healthy 

 statė during the six months they were alive in my possession and 

 during the four months they were in that of Bond. A member 

 present stated, that while they vvere in the gardens he had mi- 

 croscopically examined the lamellae or branny scales which are 

 ever separating, in larger or smaller particles, from the epidermis of 

 animals, and found them the natūrai and healthy production. My 

 own examination of these exfoliations had led me to the šame opinion. 

 I had the opportunity, and carried my inquiry still further ; I care- 

 fully examincd the surface and sections of the dermoid coveriug with 

 low and with high microscopic povrers, and vath. transmitted light, 

 and as opake objects, ^vith a view to discover any hair follicles or 

 glandular bulbs from uhich hairs might have emanated, but could 

 not discover a single indication of either, uor any recognizable vestige 

 of their obliteration ; — 1 therefore believe the organs for pilous pro- 

 duction were absent, and ab initio. These little animals haviiig been 

 found in a straw-rick, I conclude, will sufficiently indicate their habits 

 and general resideuce to be similar to those of the common mouse. 



Note. — Having recently heard that a specimen of the šame variety 

 of Mus that I have described is preserved in the Museum of the 

 CoUege of Surgeons, I compared it with the examples I possess, and 

 found it precisely the šame in every character ; it was caught by 

 the late Mr. Clift in the fire-place of a room in his house in London, 

 and is eutered in the Catalogue of Monsters — " No. 121 . A common 

 Mouse {Mus Muscuhts), full-grown, which, from its birth, had not 

 tlie slightest appearance of hair on its skin, being perfectlv naked. 

 Presented bv Mr. Clift, 1820." 



