44 



strise) are sometimes obliterated on the cast, they are always clearl}^ 

 defined when the shell is preserved. In the last whorl of a large but 

 distorted specimen, seventeen of these rib-like spaces can be coiiiited, 

 which average about a quarter of an inch in width, the grooves being 

 about half as wide. It is scarcely correct to call the spaces between the 

 grooves ribs, for, although the furrows sink deeply below the general 

 level of the surface of the shell, there are no corresponding elevations 

 above it. Sometimes the spaces are as much as half an inch wide. 



The outlines of the septa can only be traced in a half-grown specimen 

 (the original of Plate II., fig. 2) and in it they are partly covered by the 

 shell. The siphonal (" dorsal ") saddle is small, simply conical and entire. 

 Its sides are slightly convex, but they are not toothed or cut. There are 

 two bipartite lateral lobes and saddles, with bifid terminations, on each 

 side. The first lateral lobe, which is the largest, is about as long as the 

 siphonal one. The number of accessory lobes and saddles between the 

 umbilical margin and the sutures of the whorls cannot be made out very 

 satisfactorily, but as the second lateral lobe is jDlaced on the edge of the 

 umbilicus, they must be very few. 



Five specimens of this species were collected, three of which are either 

 imperfect or much distorted. 



These shells agree exactly, both in shape and sculptm'e, with the 

 figures and descriptions of Ammonites Sacya, Forbes, as given in the 

 " PaliBontologia Indica." Stoliqzka's illustration of the type of A. Buddha, 

 Forbes, (a synonym of A. Sacya) would serve as a portrait of the specimen 

 represented at Plate II., fig. 3. Yet the septation of the two species 

 is not alike, the principal difference being in the shape of their siphonal 

 saddles. Those of A. Sacya are said to be tongue-shaped and toothed, 

 ("sella siphonali denticulata, linguiforme") while those of A. filicinctus 

 are conical and entire. 



A. filicinctus is also nearly allied to A. quadrisulcatus, D'Orbigny, 

 especially in the outlines of its septation, the siphonal saddles being of the 

 same shape in each. A . quadrisulcatus was at first imperfectly described 

 (in the " Paleontologie Fran§aise") from half-grown casts. It has since 

 been illustrated rather copiouslj^ by Zittel, in the " Cejihalojjoden 

 der Stramberger Schichten," also in the "Fauna der Aelteren Cepha. 

 lopoden Fuehrenden Tithonbildungen," and Tiitze has figured a variety 

 of it in the " Jahrbuch der Kaiserlich-Koniglichen Geologischen Eeich- 

 sanstalt" of Vienna, Vol.. XXII., (1872^ Plate IX-, figs. 12a and 126. In 

 Zittel's diagnosis of A. quadrisulcatus no mention is made of any trans- 

 verse striae, although some rather distant ones are represented in his 



