ANNIVERSARY ADDRESS OF THE PRESIDENT. Ixiii 



followed by the genera Rhynchonella with fourteen species ; Argiope, 

 one ; Crania, one. To this the author has added a table illustra- 

 ting the geological distribution of all the British Cretaceous Brachio- 

 poda, the total number of which is forty-nine. In his supplementary 

 observations on the stratigraphical distribution of the species, Mr. 

 Davidson remarks on M. d'Archiac Jiaving stated in his ' Histoire 

 des Progres de la Geologic/ that the British cretaceous strata contain 

 fifty-two species of Brachiopoda ; he observes that his own list of 

 forty-nine greatly exceeds in reality the number of true species 

 recorded in M. d'Archiac' s table, inasmuch as at least twenty-two or 

 twenty-four of M. d'iVrchiac's names are only synonyms, whereas 

 his list contains a number of species new to England and not men- 

 tioned in any other publication. Still he admits the possibility of 

 error, and observes that possibly the number of hitherto observed 

 species in the British cretaceous strata may not exceed forty-five, 

 and adds that the correctness of this number must also depend upon 

 the correctness of the age of certain other beds, particularly the 

 Farringdon gravel, a question into which he enters at some length. 

 It is impossible to praise too highly the execution of the seven 

 plates by which this portion of Mr. Davidson's work is illustrated. 

 In the Appendix, and the supplementary additions to the Appendix, 

 the author has introduced certain corrections and addenda, with an 

 additional plate, bringing down our knowledge of the subject to the 

 last moment of publication. 



The next essay to be noticed is the second part of Prof. Owen's 

 Monograph on the Fossil Reptilia of the Wealden Formations, con- 

 taining the order Binosauria and genus Iguanodon. The paper is 

 illustrated by nineteen plates, some of very large size, representing 

 different portions of osseous remains of the Iguanodon, many of 

 which are drawn to the natural size. The text descriptive of these 

 illustrations is a favourable specimen of Prof. Owen's well-known 

 power of comparing and elucidating the osteology of the fossil Verte- 

 brata. I would particularly call attention to the lucid manner in 

 which he has pointed out the real analogies and nature of that 

 curious specimen so long considered, on the authority of Dr. Mantell, 

 to be the bony core of the frontal horn of the Iguanodon. Prof. 

 Owen shows, on grounds which appear to be incontrovertible, that 

 this fossil relic is in fact one of the phalangeal bones, and he sums 

 up the evidence he brings forward to show that it belonged to the 

 end of one of the toes instead of to the head of some great Wealden 

 Saurian, by pointing out the characters which separate the gigantic 

 Iguanodon from the little modern Iguana, which has an osseous 

 conical horn or process on the middle of its forehead. 



This is followed by the Monograph by Prof. Morris and Mr. 

 Lycett on the Mollusca from the Great Oolite. The specimens are 

 derived chiefly from Minchinhampton and the coast of Yorkshire, 

 and this third part contains the completion of the Bivalves. It is 

 accompanied by seven plates representing the species described, of 

 which I need only say that their execution is worthy of the place 

 they occupy in the volumes of the Palaeontographical Society. 



