74 University of Texas Bulletin 



lying nearer the antisiphonal lobe and making the more dorsal division 

 smaller than the more lateral one. The antisiphonal lobe is peculiarly 

 narrow and elongated, and has a slightly inflated, bifid tip. 



The suture has the same number of elements, six lobes and six saddles, 

 as Ptychoceras, and the species seems to have some resemblance to 

 P. laeve, var. hamaimensis Pervinquiere 1 (Lower Gault, Tunis) ; however, 

 the first two saddles of our species are broader and less dissected; the 

 third saddle is unequally and shallowly bifid ; the first lateral lobe is 

 trifid instead of bifid ; and the other lobes are bifid. The African species 

 also differs greatly in form from ours, in having two apposed limbs and 

 annular constriction and inflations on the thicker limb. The Texas Upper 

 Cretaceous (Navarro) species Ptychoceras texanum (Shumard) 2 has the 

 two limbs strongly ribbed and closely apposed. 



BACULITES COMANCHENSIS n. sp. 



PI. 2, figs. 20-22 

 1920: Baculites sp., Winton and Adkins, Univ. Texas Bull. 1931, pp. 21, 69. 



MEASUREMENTS : 



I (type) II III 



Length 12.5 17.3 13.4 



Smaller end, major diameter 3.3 4.0 3.9 



Smaller end, minor diameter 2.9 3.4 3.0 



Number of ribs in 5 mm 5 1-2 



Larger end, major diameter 6.1 



Larger end, minor diameter 3.4 3.7 3.1 



Number of ribs in 5 mm 4 1-2 3 



A characteristic Pawpaw baculite lacking the aperture and the coiled 

 portion, will be described here on account of its stratigraphic importance. 

 The straight portion is preserved with the sutures, as a limonite cast. 



HORIZON : Pawpaw formation, clay facies, base, rare. 



LOCALITIES: Individual II from locality 714, near Fort Worth, 

 Texas; type individual (PL 2, fig. 21) and the others from locality 719, 

 wes t facing hill to east of Crowley road, one! mile south of the Baptist 

 Seminary, four and a half miles south of Fort Worth, Texas. 



DESCRIPTION: Straight fragments preserved, slightly and uni- 

 formally tapering, lateral outlines slightly undulating but on the whole 

 straight; cross-section a short oval; living chamber not preserved, but 



'Et. pal. tun., p. 90, pi. IV, figs. 5, 6a-b. 



c. Bost. Soc. Nat. Hist., 8, 1861 (1862), p. 190. 



