161 Geology and Natural History. 



thick, massive body, and broad, but comparatively thin jaws, 

 which are also different in form. Some of the differences in size 

 and proportions, and in the suckers, observed among the four 

 specimens referred to the latter species, may be due to sex, for 

 the sexes differ considerably in these characters in all known 

 cuttle-fishes. 



19. Jievision of the Echini ; by Alexander Agassiz. Part 

 iii, 4to, with 45 plates. Illustrated Catalogue of the Museum of 

 Comparative Zoology, (^^ambridge, Mass. IS^S. — This excellent 

 work is profusely illustrated by unique plates, a large part of which 

 have been made by different ])hotographic printing processes, di- 

 rectly from photographs of the specimens, and are of unrivalled 

 excellence. The Woodbury-type process, the Albert-type and the 

 Heliotype, have all been successfully employed, while superior 

 lithographs have also been used to some extent. Part iii. contains 

 detailed descriptions of all the known species, except those of the 

 east coast of North America, which were described in Part ii. 

 Such species are, however, referred to, in their proper systematic 

 places. Twenty-eight plates illustrate Part iii ; the remaining 

 seventeen relate to structure and belong to Part iv, but are issued 

 in advance of the text, owing to the loss of the MSS., drawings, 

 and some of the plates, by the great Boston fire, in November, 

 1872. " A. E. V. 



20. The Marine Mammals of the Northioestern Coast of North 

 yimerica, described and illustrated, together with an account of 

 the American 'Whalefshery / by Charles M. Scammon, Captain 

 U. S. Revenue Marine. San P^rancisco : John PI Carmany & Co. 

 4to. — The advance copies of the plates of this work, that we have 

 seen, are highly satisfactory, and considering the well known ability 

 and enthusiasm of the author, we anticipate that the book, when 

 com|)leted, will be a valuable contribution to science, in a depart- 

 ment which is still very imperfectly understood, and of great im- 

 portance economically. The work deserves, and should receive, 

 the support of all who are interested in j^romoting the study of 

 Natural History. It is to be illustrated by thirty or more litho- 

 graphic plates, and is offered to subscribers at the very low cost 

 of ten dollars. a, e. v. 



