Book Notice. 219 



To sum up, Am. serpentinus, (Rein, sp.), Am. falcifer (Sow. 

 sp.), and Am. strangwaysi, (Sow. sp.) are distinct species. In 

 Yorkshire, we appear to have two forms — one very common, 

 which seems to be the adult of falcifer, and therefore would 

 be named Harpoceras falciferum, the other, an allied form, 

 which should be kept distinct under the name Harpoceras 

 mulgr avium. 



It is my most pleasant duty to thank Mr. Buckman, who, 

 with generous self-sacrifice, • has placed at my disposal the 

 materials for the first plate, and especially for his advice ; 

 Mr. J. W. Tutcher, for the use of his valuable photograph of 

 Young and Bird's type, which was needed to complete the paper; 

 Dr. A. Smith Woodward, for the very necessary photographs 

 of Sowerby's types, and for the use of the British Museum 

 (Natural History) Library ; Mr. Sheppard, for the photograph 

 of the Yorkshire specimen in his charge at the Hull Museum ; 

 and Mr. J. W. Stather and Dr. Walton, for procuring for me 

 some of the requisite literature. 



It is obvious that without this generous help the present 

 paper could not have been prepared. 



I wish also to thank the editors for so liberally illustrating 

 the paper, and so enabling photographs of all the types under 

 discussion to be seen together for the first time. 



LIST OF WORKS OF REFERENCE FOR ABOVE PAPER. ^ 



181 8, Reinecke, I. C. M. — 'Maris protogaei Nautilos et Argonautas,' 

 etc. 



1820, Schlotheim, E. v. — ' Die Petrefactenkunde,' etc. 



1820, Sowerby, J. — ' Min. con.', Vol. III., p. 99, t. 254. 



1822, Young, G. and Bird, J. — 'A Geological Survey of the Yorkshire 

 Coast.' 



1842-49, Orbigny, A.d'. — Paleontologie Fran9aise. Terrain Jurassique, 

 t. I. 



1876, Tate, R., and Blake, J. F. — ' The Yorkshire Lias.' 



1878-86, Wright, T. — ' Monograph on the Lias Ammonites. 



1884, Simpson, M. — ' The Fossils of the Yorkshire Lias," 2nd Edition. 



1887 and 1889, Buckman, S. S. — On Jurassic Ammonites, ' Geol. 

 Mag.', dec. III., Vol. IV., p. 396 ; and Vol. VI., p. 200. 



We have received 'Book Auction Records' (Vol. VI., part i), pub- 

 lished by Karslake & Co., London. This book is issued quarterly at 

 a subscription of £1 is. per annum. The part before us contains 3383 

 records of sales made during the quarter ending December 31st, and from 

 the numerous details given relative to each lot, is a most useful guide to 

 the librarian or private collector. The present number contains ' Notes 

 on Hull Authors, Booksellers, Printers and Stationers, etc.', by Mr. W. G. B. 

 Page. 



igog June i 



