AMMONOIDEA. 77 



shows the characters aboye mentioaed, which are sufficient to establish it as a new 

 species. Unfortunately the exact horizon from which this specimen comes cannot 

 be ascertained. 



The second specimen, which was collected by Mr, Griesbach in his horizon 4, 

 is still more damaged, but it shows distinctly the sharp siphonal side, so that not- 

 withstanding it being too imperfect to allow of an examination of the sutural line, 

 I have no doubt that it belongs to the species here described. 



Sphenodiscus acutodorsatus is therefore chiefly characterized by its sharply- 

 keeled siphonal side, by which it is readily distinguishable from the broader Indoceras 

 halucHstanensis. The sutural line exhibits also some marked differences ; in the 

 former the external saddle is divided by a rather deep secondary lobe, while in 

 Sphenodiscus acutodorsatus it is divided by ^mjo secondary lobes into three branches. 



Genus: BAG QLITES, Lamarck. 



Baculites binodostjs, spec. nov. PI. XXIII, fig. 3-3a. 



A fragment of a specimen 90 mm. in length represents this genus ; as it is 

 chambered throughout, the complete shell must have been of considerable length. 

 At the lower end the dorso-ventral diameter measures 24 mm., at upper end 31 mm., 

 so the missing part towards the embryonic chamber of the shell cannot have there- 

 fore measured less than 250 mm., and the complete shell must have attained a length 

 considerably over 340 mm. 



The greatest lateral diameter, which is close to the antisiphonal side, is 14 mm. 

 at the lower end and 18 mm. at the upper end, but it decreases considerably towards 

 the siphonal side. The cross section is therefore egg-shaped. 



The sides are flat and slope towards the rounded siphonal side; the antisi- 

 phonal is rather broad and somewhat flattened. On either side of the latter there is 

 a row of very indistinct, low and broad tubercles, which are, however, only visible 

 under a favourable light. 



The siphonal lobe is rather broad, but not very deep ; the first lateral lobe is 

 narrow, deeper than the siphonal lobe, and bipartite ; the second lateral lobe is broader 

 than the first, but much less deep, also bipartite ; the antisiphonal lobe is very short 

 and narrow, and terminates in one point. The external saddle is narrow and high, 

 but much less so than the first lateral, which is the highest, and bipartite like the 

 former ; the anti*<iphoaal saddle is broad and low. Saddles and lobes are deeply 

 denticulated. 



Locality and stratigrapkical position. — Des valley : exact horizon unknown, 

 but it is most probable that this specimen was found together with Sphenodiscus 

 acutodorsatus, spec. nov. 



Bemarks. — The specimen above described was given by Mr. R. A. Townsend, 

 who collected it in the Des valley near Khattan, to Mr. Oldham. Its characters are 

 sufficient to establish a new species. It differs from the other known species chiefly 

 by the character of the sutural line; BacuUtes baculoides, d'Orbigny, resembles th© 



