38 PSEUDOCERATITES OF THE CRETACEOUS. 
shoulders and the rapid slope of the lateral zones and subacute character 
of the venter. The costz are linear and only slightly curved in the only 
well-preserved part of his type as figured. The involution covers about 
three-fifths of the next inner whorl, leaving a rather large open umbilicus 
showing the younger whorls. 
The more discoidal form (pl. 2, fig. 2, and pl. 3, fig. 2) supposed to 
belong to this species, is certainly distinct specifically and may be nearer 
to Pseudotissotia than to any species of this genus, but it is too imperfect to 
give diagnostic characters. 
Locality: North Africa. 
Age: Turonian. 
CHOFFATICERAS? DOUVILLEI (Peron). 
Pseudotissotia dowvillei Peron, 1896, Mém. Soe. géol. France, Paléontologie, Vol. 
VI, No. 17, pl. 2, figs. 4, 5, and pl. 3, figs. 3, 4. 
This species, as figured and described by Peron, has the general form 
and aspect of C. meslei, but the heavy nodes on the umbilical shoulders 
and dichotomous coste reaching to the sides of the prominent keel are 
auite different. 
Locality: North Africa. 
Age: Turonian. 
HEMITISSOTIA Peron. 
This genus seems to me to be more intimately related to Choffaticeras 
than to Tissotia and other genera having similar forms but having sutures 
with smooth saddles. Such questions can only be definitely settled when 
the younger stages become known. These involute and more or less com- | 
pressed forms with trenchant keeled venters are apparently in the direct 
line of modifications indicated by the similar forms of Tissotidee, but on 
the other hand their sutures correlate with the more complex outlines of 
those of Pseudotissotia and Choffaticeras, and this indicates that they are 
simply parallel as representative forms analogous to some of the Tissotide 
but really in the genetic line of Choffaticeras. They have retrogressive 
characters in the undivided outlines of their inner saddles, but this arrest 
of development has not affected the outer saddles that are completely 
digitated. They can not be placed anywhere in the genetic line between 
Pseudotissotia and Subtissotia on account of the absence of channels and 
