PSEUDOTISSOTIID.X. 39 
ridges on either side of the keel, and this is the only position that could be 
claimed for them in view of their peculiar sutures. All of their characters 
accord best with the view that they are direct descendants of Choffaticeras. 
There is an interesting group of this or an allied genus from the Senonian, 
described by Choffat in his Céphalopodes de la Faune Crétacique du Portu- 
gal, Vol. I, 2d series, but the condition of the specimens did not permit 
him to describe them sufficiently to judge closely of their affinities. 
HeEmitissoTia CAZzINI Peron. 
Hemitissotia cazini Peron, 1897, Mém. Soc. géol. France, Paléontologie, Vol. VII, 
No 17, pl. 14, figs. 1-5; pl. 18, figs. 9, 10. 
This species is a highly involute compressed form, and in the oldest 
specimen figured the first and second lateral saddles are completely 
denticulated, the third is equally divided by a median marginal lobe in the 
figure of the suture of the oldest specimen (pl. 18, fig. 9), but this is not 
described in the text. ; 
Locality: North Africa. 
Age: Senonian. 
Hemitissotia? BaTNENSIS Peron. 
Hemitissotia? batnensis Peron, 1897, Mém. Soc. géol. France, Paléontologie, Vol. 
WATTEON GO alicopla lion host a(S 
This species has the external aspect of this peculiar group and the 
sutures are similar as figured by Peron, but his question mark after the 
generic name is justified by the Sphenodiscus-like aspect of the first lateral 
saddles. 
Locality: North Africa. 
Age: Senonian. 
HEMITISSOTIA MORRENI (Coquand). 
Hemitissotia morreni Peron (pars), 1897, Mém. Soe. géol. France, Paléontologie, 
Vol. VII, No. 17, pl. 15, figs. 1 and 2 only, and pl. 18, fig. 11. 
Hemitissotia morrent var. precipua, ibid., p. T7. 
This var. precipua of Peron is a highly compressed form with acute 
venter. Pl. 15, fig. 8, may be the young of this species, and if so, it shows 
conclusively that it is distinct from the following. 
Locality: North Africa. 
Age: Senonian. 
