78 PSEUDOCERATITES OF THE CRETACEOUS 
the external layer is also nacreous. The growth ridges certainly give the 
aspect of an external shell, but this may be due to the fact that the second 
or middle layer takes the lines as impressions from the outer layer, which 
is absent in this and in the larger fossil also. his last has a very distinct 
nonnacreous or only faintly nacreous inner layer; the middle layer is 
brilliantly nacreous, as usual, but the lines of growth, although present, are 
not so well marked as in the smaller specimen. In both specimens these 
lines indicate a well-marked rostrum with broad lateral sinuses, median 
lateral, broad crests—similar broad sinuses internally rising toward the 
umbilical shoulders. The diameter was partly estimated at 157 mm.; the 
diameter of living chamber, which is nearly complete and one-half of a 
volution in length, is about 90 mm. at aperture. 
A east from South Carolina (Coll. American Museum of Natural 
History, New York), is 151 mm. in diameter. The living chamber is a 
trifle over one-half of a volution in length where complete on the umbilical 
shoulder. The form and other characters are like those of lenticularis and 
the saddles have exactly the attenuated outlines given in Meek’s pl. 34, but 
are much shorter, and are also quite distinct from those of Meek’s other 
figures of this species. The auxiliary saddles have the peculiar phyllitorm 
bases given in that figure. The inner edge of aperture is present on one 
side and shows that internally the living chamber was about one-half of a 
yolution in length. The venter was solid. Steinmann, in his Elemente 
der Palaeontologie, Vol. II, p. 415, figures a specimen said to be from 
upper Missouri, with the typical suture line of this species, but having a 
line of median lateral nodes. He gives four derivative lateral saddles, but 
there are, in my opinion, only three, the remainder belonging to the 
auxiliary system. The nodes may be the immer termini of the coste, 
perhaps slightly more prominent than usual. True nodes are not present 
in any specimen I have seen. 
SPHENODISCUS BEECHERI n. sp. Hyatt. 
Pl. VI,-figs. 3, 4; Pl. UX, fig: 10: 
The type of this species is a large specimen in Collection of the Museum 
of Comparative Zoology, labeled ‘Central City, Colorado,”* but the real 
«Mr. Stanton has most kindly corrected this as follows: ‘‘This locality is an error. Central City 
is in the midst of a granitic region and 30 or 40 miles from the nearest Cretaceous outcrops.” 
