ORDOVICIAN FAUNAS. 175 
the dorsal slopes gently convex and distinctly undulated by strong, 
shightly-curved, transverse furrows and subangular ridges; the ven- 
tral or umbilical slopes almost flat and usually without undulations ; 
ventral side with a sharp, central furrow for the reception of the dorsal 
carina of the preceding volution. Umbilicus well-defined, wide and 
deep, the edge wavy. Aperture a little wider than high, the height 
a little more than half the greatest diameter of the shell, more or 
less rhombic-subquadrate in outline. 
The dimensions of the best-preserved specimen observed are: great- 
est diameter, 11.5 mm.; width of aperture, 8.5 mm. 
Remarks.—Vhis variety of Cyrtolites ornatus differs only from the 
typical form of the species in its smaller size. The variety is the 
older form, being known only from the Trenton, while the larger, 
more typical form occurs in younger beds. But few individuals have 
been observed in the New Jersey collections, and all of these are 
internal casts, so that the delicate surface markings of the species 
cannot be seen. These markings consist of delicate, raised lines, run- 
ning almost straight across the volutions, with short, connecting lines 
arranged alternately. 
PROTOWARTHIA CANCELLATA (Hall). 
Plate hicsia—n: 
1897. Protowarthia cancellata U. & S., Pal. Minn., pt. IL., p. 872, 
pl. 63, figs. 1-14. 
Description.—Shell of medium size, subglobose, close coiled, with 
no umbilicus when the shell is preserved, but with a small one in the 
casts. In immature specimens the dorsum of the outer volution is 
rather sharply rounded, but with increasing age it becomes more 
broadly rounded, losing entirely the obscure carination of the younger 
shells. Sinus shallow, rounded; the lateral margins of the aperture 
on either side of the sinus regularly and rather gently convex. Aper- 
ture wider than high, subsemi-circular in outline. On the larger in- 
ternal casts one or more rather broad and shallow, rounded, transverse, 
wrinkle-hke depressions are frequently present near the aperture and 
parallel with the apertural margin. 
