BUCHICERATID.®. 33 
RoEMEROCERAS ATTENUATUM (Hyatt). 
Pl. I, fig. 15. 
Buchiceras attenuatum (pars) Hyatt, 1875, Proc. Boston Soc. Nat. Hist., Vol. XVII, 
p- 372. 
The cast differs from syriaciforme in having more numerous nodes on 
the inner line. On the outer volution, at a diameter of 64 mm., there are 
about nine on the inner row and sixteen on the outer, whereas in syriaci- 
Jorme, at a diameter of 90 mm. there are seven on the inner line and eleven 
on the outer line; in another specimen of syriaciforme, at a diameter of 
73 mm., there are the same number; in another, at a diameter of 34 mm., 
there are six on the inner and fourteen on the outer line; in another, at a 
diameter of 41 mm., there are seven on the inner line and fifteen on the outer. 
There are faint signs of a keel on the type specimen, showing that it 
belongs in this genus. The general form is much more compressed than 
that of R. syriaciforme ; the venter is narrower and the keel is also less devel- 
oped. The volutions are more enveloping, and the umbilicus is smaller. 
The specimen is a cast, partly crushed on one side and somewhat worn on 
the other, but although the sutures are not consequently perfect they are 
entirely distinct from those of other species. The first lateral lobes are bifid 
and shorter than the ventral lobe. Instead of being of about the same 
length or longer than the ventral, as in R. syriaciforme, all the saddles are 
broad and very short, as are also the lobes. The first lateral saddles and 
lobes are completely denticulated by marginals. The second lateral is trifid, 
the third and fourth saddles are bifid, and there is a fifth saddle, but this is 
on the line of involution and very narrow. The second lateral lobes are 
trifid. The third lobe is in the umbilical zone and bifid, but otherwise entire, 
and the fourth is very small and apparently entire, but too much worn to 
make observation certain. 
There are incrusting ostreans upon both sides of this cast and they 
appear to have been attached to a fossil cast. 
This species is founded upon a single fossil cast, one of the two used 
for the description of Buchiceras attenuatum Hyatt, but not the type. The 
latter is to be found on page 151, under the name of Anemiceras attenuatum 
Hyatt. 
Locality: Celendin, Peru. 
Age: Upper Cretaceous. 
MON XLIV—03 3 
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