No. 1.] BOTANY AND ZOOLOGY. 55 



passing through a series of modifications, always in one direction 

 and tending constantly to elongation, affords at length the acicu- 

 ■ lar type. To this is opposed (most frequently, but not exclusi- 

 vely in the lower tribes, and even possibly anticipated by the 

 polar bilocular sub-type in Parmeliacei) a second (typically 

 coloured) in which the simple spore, completing another series of 

 chano-es, tendino; rather to distention and to division in more 

 than one direction, exhibits finally the muriform type," A con- 

 sidenition of these spore and other distinctions has led to con.- 

 siderable changes in the grouping of the species. A critical 

 reference to these would interest the working lichenologist 

 rather than the general student, and in this place we therefore 

 need not more than say that the whole of these little organisms 

 are, in the work before us, divided into five tribes whose characters 

 are dependent chiefly on the external structure of the apothecium. 

 These are sub-divided into families under which the genera are 

 arranged. Beyond this, it will be sufficient to instance the 

 changes in two familiar genera — the Parmelia of the old books, 

 which is separated into Theloschistes, Parmelia and Pliyscia : and 

 Lecanora which nowbecomes/^/acocZizmi, Lecanora and Rinodina. 



The book is replete with elaborate critical notes on the tribes, 

 families, genera and species ; several new species, some of which 

 are of interest to Canadians as occurring here, are incidentally 

 described or referred to ; and what is of value in connection with 

 the subject of geographical distribution, the range of species on 

 this continent is frequently indicated. 



Prof. Tuckerman's labours have been purely scientific. There 

 is not perhaps very much in the book to attract the general 

 scientific reader, but among those who make the Lichens their 

 study this volume wdll be much appreciated. — A. T. D. 



Larv^ of Worms and Echinoderms. — In a recent me- 

 moir in the Transactions of the American Academy, Alexander 

 Agassiz, shews that certain larvae named Tornaria, supposed to 

 belong to star-fishes, are really young worms of the genus Balano- 

 glossus. This, in his judgment, tends to destroy the slender 

 basis of embryological resemblance on which Huxley had endea- 

 voured to separate Echinoderms from other radiates and place 

 them with certain worms in the so-called sub-kingdom Annuloida. 

 If this is really so, it will tend to remove a perplexing anomaly of 

 classification w^hich has already found its way into many text 

 books of Zoology and Palaeontology. 



