PHYLLOCERAS HETEROPHYLLUM. 425 



Ammonites Terverii, (TOrbigny. Paleont. rran9., Terr. Cret., t. i, p. 179, 



pi. 54, figs. 7—9, 1840. 



— HETEROPHYLLUs, — Paleontol. Fran9aise, Terr. Jurassique, torn. 



i, p. 339, pi. 109, 1842. 



— — Simpson. Ammonites Monogr., p. 7, 1843. 



— — Quenstedt. Flozgeb. Wurterab., p. 259, 1843. 



— — Morris. Catalogue British Fossils, p. 173, 1843. 



— — Quenstedt. Cephalopoden, p. 99, pi. vi, figs. 1 — 5, 



1849. 



— — Oppel. Die Juraformation, p. 251, 1856. 



— — Quenstedt. Der Jura, p. 252, pi. 36, fig. 4, 1858. 



— — Dumortier. Depots Jurassiques, t. iv, p. 101, 1874. 

 Phtlloceras heteeophyllum, Neumayr. Zeitschr. Deutsch. Geol. Gessellschaft, 



Bd. xxvii, p. 903, 1875. 

 — — Tate and Blake. Yorkshire Lias, p. 297, 1876, 



Dimensions. — The figured specimen. Transverse diameter 410 millimetres. 



Description. — The magnificent specimen figured in PL LXXVIII, fig. 1, is, as far as 

 I know, a unicum, which I discovered in the collection of the late Mr. Marshall, 

 of Whitby, jet-dealer, many years ago. It was so different to any other Ammonite I 

 had ever seen that I at once secured it for my cabinet. My old friend, Dr. S. P. Wood- 

 ward, was with me when I made the purchase, so that, when we had realised the rarity 

 and value of the fossil I had bought, he pleaded hard with me to part with it to the National 

 Collection, which I accordingly did. Up to that time the true anatomy of the shell of 

 Am. leteropliyllus. Sow., was unknown, as the specimens contained in public collections, 

 ■and which had formed the subject of published figures of the species, were inner whorls, 

 mostly destitute of the shell, so that when the body-chamber was seen in situ in 

 the grand specimen we had found, its value became enhanced accordingly. My 

 figure is drawn just half the natural size, and displays the body-chamber of the shell 

 in all its beauty, with the test finely preserved and ornamented with striae, — that 

 important portion which had been unknown before. The inner whorls had been figured 

 by Sowerby, Buckland, and d'Orbigny, but the fan-like body-chamber was absent in 

 their specimens. M. Dumortier figured two fragments of the shell of the fan of 

 this species as " corps de nature inconnue," and observed that the bodies, of which a 

 drawing was given (Dep. Jurass., partie iv, p. 228, pi. xlviii) of the natural size, were 

 found in Thiolliere's collection ; with the two specimens was a note in the handwriting 

 of V. ThioUiere : — ' Minerai du Lias Superieur de la Verpilliere ; fouilles pres de Serres ; 

 donnes par M. Drian, Octobre, 1854.' "The principal fragment has the appearance 

 of a leaf with very large undulations, the surface is covered with ribs, or regular flutings, 

 up to the number of twenty or so on each undulation. On these ribs we notice the indi- 

 cations of smaller nodosities irregularly disposed ; nevertheless, we think we recognise the 

 tendency to a concentric serial disposition. The ribs and the large undulations have a 

 fan-like disposition, as if they took their origin from a single point, which is absent from the 



