ENGONOCERATID &. 165 
ENGONOCERAS PIERDENALE (von Buch). 
Pl. XX, figs. 6-13. 
Ammonites pierdenalis yon Buch, Abhandl. K. Akad. Wiss. zu Berlin, 1848, pl. 6, 
fies. 8-10. 
Ammonites pedernalis Roemer, 1852, Kreideb. vy. Texas, Pl. I, fig. 3. 
Engonoceras pedernalis Bohm, 1898, Zeitschr. Deutsch. geol. Gesell., Vol. L, p. 183. 
I have placed this here with a query, because I find it impracticable to 
identify the young figured by von Buch with any form known to me. 
The ventral lobe and saddle and the other parts of the suture might belong 
to the young of a species a grade more complicated than any here described. 
There is a row of elongated nodes close to the venter in von Buch’s figure, 
but the presence of such ornaments is denied in the text, and the nodes are 
said to be on one side and due to the exposure of the joints of the siphuncle. 
Roemer states that he had the originals in hand when making his deserip- 
tion, and that the species was much larger than that described by him. 
Neumayr mentioned this species as the type of his genus Engonoceras* 
and repeats the name ‘‘pierdenalis” instead of ‘“pedernalis,” the name given 
by Roemer, and also repeats von Buch’s figure of the suture on PI. 7 ot 
Uber Ceratiten. 
Von Buch and Neumayr also both describe the principal saddles as 
bifid, a condition that does not exist in any specimen of the genus that I 
have seen. 
Locality: Texas. 
Age: Fredericksburg group of Comanche series. 
EXNGONOCERAS PIERDENALE variety COMMUNE Hyatt. 
JBL, ROG we, Al, 
A fragment in U. 8. National Museum, No. 8301b, from Bell County, 
Tex., is slightly crushed in the umbilical region, but has sutures and mark- 
ings well preserved. At larger end the volution is 33 by 14 mm., at smaller 
end 24 by 11 mm. 
The venter is flattened and narrow, bordered by small elongated 
tubercles rather numerous and closely set as in the adults of this species. 
There is an inner row of tubercles, hardly perceptible median row, and 
equally faint fold-like costations on the outer part of the volution, which 
can be felt better than seen on this cast. 
«Amm. d. Hilsbild. Norddeutschlands, Paleontogr., Vol. XX VII, 1880-81, pp. 138, 141. 
