COILOPOCERATID 4. 99 
There were three principal lateral lones and the third was the remnant 
of the primitive lateral lobe. 
The dorsal sutures were seen in the gerontic stage and a partly restored 
outline of the antisiphonal is given in Pl. XII, fig. 3. The right outline and 
the end of the lobe are restored. The extreme bifid end of this lobe was, 
however, seen from below. The first dorsal saddle was clearly seen but 
was apparently abraded like the antisiphonal, and the remaining saddles 
were seen, but not in such connection as to make a drawing desirable. 
They correspond in outlines to the opposite lobes and saddles of the aux- 
iliary series, being entire and phylliform near the lines of involution and 
trifid near the first pair of dorsals. The lobes also are digitated like their 
Opposite companions of the auxiliary series. There are six pairs of saddles, 
with a seventh continuous. with the eleventh outer saddles, and six pairs of 
lobes, the antisiphonal making the thirteenth lobe on the dorsum. 
Locality: Rit du Plain, Colfax County, N. Mex. 
Age: Colorado group, Upper Cretaceous. 
COILOPOCERAS REQUIENIANUM (V’Orbigny). 
Ammonites requienianus VOrbigny, 1840, Terr. Crétacé, pl. 93. 
The suture given by dOrbigny has a large first lateral, but it is narrow, 
long, and bifid, with a third arm on the external side. The two next saddles 
have the relations common in this genus, the second being hardly distin- 
guishable as an independent saddle, narrow, phylliform and bifid, while the 
third, which is large enough to be ranked as an independent saddle, is 
narrow, phylliform, and trifid. The auxiliary series has the broad complex 
saddle to begin with, reckoned in these descriptions as the fourth lateral, 
and the remaining saddles have the usual phylliform bases, all that are 
drawn, four in number, being bifid. 
The outlines approximate more nearly to those of the phylloceran group 
like Aconeceras nisum. The siphonal saddle, if correctly drawn, is interme ~ 
diate in aspect between the broad ventrals of other species of this genus 
and those of such forms as Platylenticeras heteropleurum, with narrower 
siphonals. 
Locality: Uchaux, France. 
Age: Turonian. 
