Bibliographical Notices. 229 



'n appearance from the normal form, but having m themselves a very 

 suspicious shape. How much caution should be employed in using 

 the shape and subdivisions of the sporidia will be evident from the 

 following passage of Montague's ' Cryptogames de Cuba' (p. 154) : 

 — "Malgrc la forme en apparence dissemblable sous laquelle se sont 

 presentees les sporidies a M. Fee et a moi, je ne puis me persuader 



que mon lichen soit une espece diiferente. Cela rCa rien 



de surprenant pour qui a analyse un grand nombre de lichens et a 

 pu voir beaucoup dt theques. J'ai observe maintes fois des sporidies, 

 qui plus tard devaient etre marquees de vingt cloisons, n'en presenter 

 d'abord qu'une seule et etre ainsi dans leur enfance seulement bilo- 

 culees." With respect to the shapes of the sporidia, it is the opinion 

 of Dr. Montague (and no one's opinion can be entitled to greater con- 

 sideration) that the sporidia of the same species, however unlike 

 themselves in their young or abnormal state, do nevertheless vary 

 but little in the same species, when well-developed. We have as yet 

 made too few observations on this obscure subject to have much con- 

 fidence in our own judgement, but both from these few and from the 

 figures and remarks of others, it appears to us to be necessary that 

 very great care should be taken not to distinguish lichens at once by 

 a difference in the sporidia, when that difference may arise solely 

 from a difference of age in the plant or from other and unknown 

 causes. Mr. Leighton's figures themselves show how much the 

 sporidia vary in the same species (see V. Hookeri, plate xxvii.). 



Although Mr. Leighton's bias is different from our own as to the 

 adjustment of species, we are far from saying that his views may not 

 often be correct, where we are disposed to entertain suspicions. His 

 careful analysis, moreover, and excellent descriptions will make any 

 errors into which he may chance to have fallen of comparatively easy 

 correction ; and the very obscurity of the subject is such that it is im- 

 possible to avoid mistakes. Some misapprehensions of his predecessors 

 have been rectified by Mr. Leighton ; many species have received 

 additional elucidation ; and several undoubtedly new ones have been 

 added. We shall look with interest to the approaching portions of 

 the work, and may perhaps afterwards discuss some subjects connected 

 with it of which we have now said nothing. 



Nereis Boreali-Amei'icana ; or Contributions towards a History of 

 the Marine Algce of the Atlantic and Pacific Coasts of North 

 Atnerica. By William Henry Harvey, M.D., M.R.I. A. &c. 

 Parti. Melanospermeae. Washington. Published for the Smith- 

 sonian Institution. London : John Van Voorst. 



The author of this very beautiful book is so well known to the 

 lovers of Marine Botany, that it is almost superfluous to do more than 

 announce its appearance. At the same time, the circumstance of this 

 being the first systematic description of North American Algae, con- 

 fers too much interest upon the undertaking to justify its being hastily 

 passed over. We must take leave to congratulate our transatlantic 

 friends upon having secured the services of Dr. Harvey, in whom are 



