24 Transactions of the Society. 



observable in these shells and the correctness of the characters 

 upon which the classification of d'Orbigny is founded " (p. 119). 

 He calls attention to the fact that the scope of d'Orbigny's work 

 is not merely the establishment of a new genus of Cephalopoda, 

 nor the discovery of " a few new species established upon insignifi- 

 cant differences, such as are proposed every day, so great appears 

 to certain minds the glory of attributing new names ; it is the 

 establishment of a new Order . . . which is freed from the chaos 

 in which it was plunged," and that here we have thirty-five {sic) 

 new genera and nearly 300 species newly discovered and established 

 after a comparative examination of all the others (pp. 119-120). 



So much for de Ferussac. D'Orbigny himself, in his own Intro- 

 ductory pages to the section devoted to the Siphoniferes and 

 larger Cephalopoda (p. 121), points out that his projected work, 

 " of which I present to-day the Prodrome," will comprise the 

 detailed description and drawings from several aspects of over 

 600 microscopic Cephalopoda, the results of six years' assiduous 

 study. He relates his early difficulties with the microscopic 

 forms, and how they were confused and confounded with the 

 larger species ; he relates tlie obstacles he had to encounter, and 

 " the optical illusions which deceived him as to the real structure 

 of the objects which he had under observation." Sometimes, he 

 says, he examined the same species twenty times before he could 

 conceive how the tiny body managed to grow and retain the same 

 form throughout its life-stages, and he pays a warm tribute to the 

 assistance and encouragement of his father, of Fleuriau de Bellevue 

 (see ante, p. 8), and of de Ferussac, under whose guidance, and 

 with whose help, he had revised and finished his work (pp. 123-4). 



We need not pause to consider the conclusions to which he 

 arrived for the rearrangement of the existing classifications. 

 At this point he gives the first of those four " Tables," which are 

 features of his works, the parts of which dealing with Foraminifera 

 I have reproduced and compared in Appendix F. The outcome of 

 his labours was to relegate all polythalamous Cephalopoda to a 

 second Order, those furnished with a siphon, which he calls 

 Siphoniferes {Si23hono%des of Haan), and a third Order {Foramini- 

 feres) comprising " the Polythalamia without any open chamber, in 

 which the last chamber which terminates the shell may even be 

 convex, and which have no siphon, having instead of it merely one 

 or more little apertures which serve for communication between 

 the chambers themselves " (p. 131). He then enumerates very 

 correctly the fundamental differences, even to the texture and 

 material of the shells, which distinguish the Foraminifera from 

 the larger Cephalopoda. 



These differences were so fully appreciated by d'Orbigny, and 

 his observations upon them were so exact, that the diagnosis he 

 gives in the introductory pages to his Third Order (p. 245) is 



