Genera of Fossil Cephalopoda. 135 



sification, and is constantly referred to in the descriptions of plants. 

 It should be studied in all its stages of development from the bud 

 to the mature fruit. The accomplishment of this will be fuund 

 easy, if the flowers of different plants be taken one after the other, 

 and their various parts carefully dissected, so as to observe their 

 number, form, position, and the relations they bear to each other. 

 We have not space here to enter into the details of naming and 

 classifying plants, and we consider it in a great measure unne- 

 cessary, inasmuch as we can refer the student to the elaborate 

 and very simplified directions upon the subject in " Gray's Les- 

 sons on Botany^'' a work which cannot be too strongly recom- 

 mended for general use, from the ability with which the author 

 has succeeded in popularising the Science of Botany and render- 

 ing its study easy and interesting. It has the advantage also of 

 containing a copious Glossary or Dictionary of Botanical Terms, 

 to which reference can be made when required. The observations 

 which bear upon the naming and classifying of plants will be 

 found in Lessons XXVIII to XXXII included, extending from the 

 17 3rd to 199th page. The ample illustrations there given will, if 

 carefully studied, impart to the yourg student sufficient knowledge 

 to enable him to discover the names of other plants in like man- 

 ner. It will be observed that Professor Gray adopts an Artificial 

 Key to the Natural Orders, and it may be mentioned that this is 

 by far the easiest method of determining the names of plants. 

 The Artificial Key will be found at the beginning of his " Manual 

 of the Botany of the Northern United States,"* which should be 

 in the hands of every botanical collector in Canada, as it is the 

 only modern woik which describes the plants that grow in this 

 Province in common with the Northern States, and of these there 

 are a vast number. 



J. B. 



ARTICLE XVII. — On the Genera of Fossil Cephalopoda occur- 

 ring in Canada. See plate II. 



In a former number of this Journal (See Vol. 1, page 315,) 

 some account was given of the Orthoceratites, and we shall here 

 resume the subject by a general description of other groups, the 

 remains of which either have been found or are likely to be 



* Gray's " Lessons on Botany " and " Manual of Botany " may be had 

 from B. Dawson, Bookseller, Great St. James-street, Montreal. 



