320 NOTICES OF BOOKS. 



form and structure of the calyptra, capsule, etc. ; and then the genera, 

 with more full characters, and the species arranged in Natural Families, 

 but to which, as in the work of Mr. W. Wilson on British Mosses, 

 no characters are assigned ; so that, but for the key on the artificial 

 system, a tyro would find it impossible to make practical use of the 

 work. 



Thus disposed, the number of genera of United States Mosses 

 amounts to 80; of species to 396; of ffepaticte, 38 genera and 108 

 species. A full Index of the genera and species follows, and then 



• • 



seven closely printed pages of Explanation of the Plates. These latter 

 are eight in number, drawn, we believe, and engraved by Mr. Sulli- 



own 



Musci and Hepat 



m 



run may read ; and our authors have, by this work, rendered the most 

 essential service to the cause of Muscology, both in America and 

 throughout Europe ; for many of the genera, and not a few of the spe- 

 cies, are identically the same in the two countries.* The arrangement 

 of these plates, and the placing several genera on each page, are at- 

 tended with this great advantage, that not only are the characters of 

 the genera clearly defined, but their resemblance to, or difference from, 

 allied genera are at once seen. 



The c Specimina Exsiccata ! are beautifully arranged in a folio form, 

 each on separate paper, so as to be easily detached, if necessary. The 

 samples are extremely perfect, and each has a corresponding number 

 with those in the descriptive volume ; and it must rank as the best 

 series of specimens of Mosses, both for beauty and scientific arrange- 

 ment, of any that has yet appeared. 



* A useful plan is here adopted of putting "Eu" (Europe) to such species as are 

 common to the two countries. Thus we find that of Sphagnum, 7 out of 16 are 

 European ; of Andreaa all are so ; of Phascum, 11 out of 17 ; of Dicranum, all (23) ; 

 of Fissideiis, 5 out of 12 ; of Trichostomum, 4 out of 5 ; of Barbula, aU the 8 ; of 

 Encalypta all (4) ; of Zyyodon, 2 out of 3 ; of Orihotrichum , 13 out of 17 ; of Pohj- 

 tnchumJSS. (5); of Bryum, 23 out of 24; of Mnium, 8 out of 9; of Bartramia, 6 

 out of 7 ; of Splachnum (veram), the only 2 species are European ; Spl. anyustatum 

 and S. mnioides are referred to Tetraplodon ; of Jnomodon, 4 out of 7 ; of Leskea, 

 2 out of 5 ; of Hypnum, 57 out of 86, etc. 



