EULOPHOCERATID A. 83 
SPHENODISCUS RUTOTI Grossouvre. 
Sphenodiscus rutoti Grossouvre, 1893, Ammonites Craie supérieure, p. 143. 
This French species is obviously closely allied to S. ubagshi, but the three 
principal laterals are very distinct from that and from any of our species. 
Age: Upper Campanian (uppermost Cretaceous.) 
SPHENODISCUS sIva (Forbes). 
Ammonites siva Forbes, 1845, Trans. Geol. Soc. London, 2d series, Vol. VII, p. 110, 
pl. 7, fig. 6. 
Sphenodiscus siva Kossmat, 1895, Beitr. Pal. und Geol. Oesterreich-Ungarns und des 
Orients, Vol. TX, pl. 22, fig. 2. 
This species, as figured by Forbes, is completely involute, smooth, and 
probably has an entire keel. It is extremely acute on the venter and highly 
compressed. There are three complex, narrow, deeply cut derivative sad- 
dles, with phylliform marginals. The venter has a prominent pointed 
siphonal saddle according to the figure. 
Age: Valudayur beds, Upper Senonian. 
EULOPHOCERATID&: Hyatt.” 
This group appears to be necessary in order to separate the remark- 
able series of forms included under this title from the Coilopoceratide. 
The forms include Tegoceras, which was, according to d’Orbigny’s figure, 
a form with a remarkably rounded volution in the gerontic stage, but 
having a venter like that of Styracoceras in the ephebic stage, and a second 
genus, which is exactly similar to Codlopoceras in form, compressed, and 
with an acute venter. All of these have peculiarly solid, low, broad sad- 
dles and short lobes, the marginals being simple and not usually branching, 
but often long, narrow, and tongue shaped. ‘The first two saddles may be 
reckoned either as one very broad saddle or as two, the dividing lobe being 
small. The auxiliaries are also very peculiar, and in Coilopoceras the inner- 
most is a long sweeping curve. So far as the evidence goes, Hulophoceras 
appears to have had a different origin from Sphenodiscus and Coilopoceras, 
as, indeed, is quite clearly indicated by the sutures. Tegoceras probably 
had a solid keel, but no direct observations have been made upon this 
part of its shell. | 
“See note on p. 84. 
