424 Beviews — Clement Reid — Origin of the British Flora. 



VI. — Mr. S. S. Buckman, F.G.S., contributes to the fifty-second 

 volume (1898) Part X of his Monograph on the Inferior Oolite 

 Ammonites of the British Islands, being a supplement to and 

 revision of the Hildoceratidse ; with 4 plates and 32 pages 

 of text. Mr. Buokman observes that " a thorough revision of the 

 genera and species belonging to the family Hildoceratid^ is 

 imperative, for two reasons: (1) because of the large accumulation 

 of material, with so many new forms ; (2) because the knowledge 

 concerning the affinities of different species has necessarily become 

 more complete." 



If Mr. Buckman can only succeed in making this most difficult 

 subject of the families and genera of Ammonites, such as the 

 Hildoceratidee, as clear to his readers as it is to himself, he will 

 have earned the thanks of all the members of the PalEeoiitographical 

 Society as well as of geologists and palasontologists in general who 

 attempt to decipher these beautiful and variable extinct Molluscan 

 shell-forms. One result of Mr. Buckman's long study of the group 

 is that he comes to the conclusion that " outward form is of merely 

 subordinate value in classification. It is obvious that species most 

 dissimilar in mere shape ^ can produce, by modification, specimens 

 which are very similar." " Hence some other criteria of affinity 

 must be sought for ; and they are to be found in the characters of the 

 ornamentation and suture-lines of the species. In comparison with 

 the mere shape, both these features are constant. They are modifiable 

 and they are modified ; but they change so much more gradually 

 than does the mere shape of the conch that they may, for practical 

 purposes, be regarded as fairly stable. At any rate, they change so 

 slowly that their identity is preserved." (p. i.) 



In regard to the relative value of the suture-line and the character 

 of the ornamentation as criteria of affinity, Mr. Buckman admits 

 that the former undoubtedly holds the premier place. He contends, 

 however, that in a group like the Hildoceratidge the ornament 

 is of great assistance. 



Mr. Buckman gives tables of his revised system of classification, 

 and we can only express a hope that they will be found capable of 

 adoption by other workers : so shall he have praise of all men. 



We congratulate the Secretary, the Editor, the Authors, and the 

 Artists on the output of monographs during the years 1897-98 

 as reflecting the highest credit on the Paleeontographical Society ; 

 and we trust that its ranks will be increased by the accession of 

 fresh recruits, so as efficiently to maintain this costly warfare against 

 the still formidable ranks of undescribed British fossils. 



II. — The Origin of the British Flora. By Clement Ebid, 

 F.E.S., F.L.S., F.G.S. (London : Dulau & Co., 1899.) 



"IHE publication of Mr. Clement Eeid's book constitutes a welcome 



and valuable addition to palseobotanical literature ; the volume 



contains in a small compass and in a clearly-written form the result 



' Perhaps the differences observed " in mere shape ' ' may be sexual, in that case 

 the offspring would be " very similar." 



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