220 PSEUDOCERATITES OF THE CRETACEOUS. 
some accident had happened fracturing the edges of the aperture on both 
sides and causing a slight sinuous constriction on both sides when growth 
was resumed. Beyond this the direction of the chevron lines was reversed 
on the right side in a median depression and on the left along a slight 
corresponding elevation. 
One fragment from Elm Fork, Dallas County, Tex., in the Museum of 
Comparative Zoology, not quite one-half of a volution in length and 
measuring 230 mm. in diameter, has these characters, but the umbilicus 
does not appear to be quite so large in proportion. The aspect of the 
saddles enables one to separate these from var. tuberculatum of P. whitfieldi, 
but it is probable that these two are connected. As I have repeatedly 
stated elsewhere, | consider this varietal connection no argument for uniting 
these obviously distinct species. This specimen has large marginal saddles 
on the siphonal saddle, and a distinct marginal median lobe, which becomes 
slightly trifid in later stages. On the left side of this are entire slightly 
phylliform saddles, and on the right a bifid marginal. These become 
subdivided later. The ventral lobe has the long arms of the whitfieldi type 
which are not similar to those of the same lobes in the syrtale type. 
I propose, in following the indications of these observations, to confine 
this name to those forms of this genus having broad venters and more 
immature sutures than in whitfieldi at all stages of growth. The edges of 
the venter may be either finely tuberculated or smooth. The sides may 
be smooth or with a median line of very obscure elevations. The inner 
line of tubercles is developed, but does not appear at an early stage. 
Locality: Elm Fork, Dallas County, Tex.; Upper Missouri, Bad Lands, 
South Dakota. 
Age: Probably Fort Pierre group, Upper Cretaceous. 
«The following note has been kindly added by Mr. Stanton: 
“ Placenticeras pseudoplacenta var. occidentale Hyatt. 
“Locality: Upper Missouri. Bad Lands, South Dakota. 
“Age: Fort Pierre group, Upper Cretaceous. 
“The specimen from the Bad Lands is certainly from the Fort Pierre, and the one from the 
Upper Missouri probably is also. 
“The specimen labeled ‘ P. pseudoplacenta var. occidentale’ and also ‘var. intermedium’ from Elm 
Fork and West Fork (Horton’s mill), Dallas County, Tex., if the locality can be trusted, is probably 
from the Eagle Ford shales, which are about equivalent to the Fort Benton.” (The locality referred 
to is trustworthy.—A. H.) 
