560 Retrospective Criticism. 



depressions so frequently met with in large masses of snow ; 

 the latter patch was probably 40 ft. long, and 8 ft. or 10 ft. 

 broad; the former one, I think, somewhat smaller: both were 

 tolerably uniform in colour, but occasionally assuming a greater 

 intensity ; not in small spots, but in portions of one or two 

 square feet, without any appearance of a central nucleus ; but 

 evidently produced by the unequal softening of the snow, 

 which had occasioned the colouring particles to be brought 

 into closer contact in some places than in others. For a mo- 

 ment the idea suggested itself that the red substance might be 

 the remains of lichens, which had originally inhabited the 

 granitic summits, rising some thousands of feet above the 

 enormous glaciers of the surrounding chains; but the suppo- 

 sition was untenable : no lichens which had become pulveru- 

 lent in such a situation could have been borne away by the 

 winds, and deposited, at the distance of some miles, in small 

 patches, without leaving a trace on the surrounding snow ; 

 nor could they have offered the same uniform appearance 

 under the microscope. The Anziendaz and Bovonnaz, which 

 rise above Bex, differ, altogether, from the St. Bernard and 

 Col de la Seigne; but, from the short passage cited by Dr. Gre- 

 ville from the work of Mr. Brown, 1 have not the slightest 

 doubt of the identity of the substance met with on the latter 

 and that found on the former mountains by M. de Charpen- 

 tier and Mr. Thomas. — P. J. Brown. Thun, Canton of Berne, 

 Switzerland, April 5. 1833, 



On the Structure of the Mowers of the Mignonettes (Reseda). 

 — Dr. Lindley has, in p. 12. of his Nixus Plaritarum, just 

 published, renounced the opinion he had previously made pub- 

 lic, and adopted that published by Dr. Brown, which he had 

 previously controverted. See Professor Henslow's treatise on 

 the same subject, reviewed in our last, p. 441., where the 

 opinions of Drs. Brown and Lindley are quoted. — J. D. 



Mr. Breeds Correction, in Vol. V. p. 753., of the Misnomer 

 in Vol. V. p. 574., of Vanessa urtlcce and V. polychlbros. — 

 I present my sincere thanks to Mr. Bree for his correction. 

 I had, as he supposes possible, somewhere seen the word 

 " polychloros" used as a generic name. — W. Gardiner, jun. 

 Dundee, April 6. 18 33. 



The Crinoideal Remains found by Mr. Conway in Mountain 

 Limestone from the Neighbourhood of Cork, Ireland, belong to 

 the Genus Cyathocrinites, not to the Genus Bncrinitcs (p. 1 26. 

 281, 282. 470.) — Sir, The plates which form the body of 

 crinoidal animals are so much better developed in some spe- 

 cimens than in others of the same species, and the whole 

 family is so imperfectly understood, that it is no wonder Mr. 



