Pa ek: 
COILOPOCERAS, ACONECERAS, SPHENODISCUS. 
Hriegsl—se Colopocenasispivng ents klnyeibtps se tart Secon a NEM ee a eae 96 
Fig. 1. Suture of right side of shell. 
.2. Suture of left side. 
3. Antisiphonal lobe and first dorsal saddle. Lower part of lobe below dotted 
line and right side is restored; the point, however, was seen to be bifid. 
All natural size. 
Rit du Plain, Colfax County, N. Mex.; Colorado epoch, Upper Cretaceous; Coll. 
Mus. Comp. Zool. 
BirGs)4—6 5 eAlconecenas:nistinyn (Or; nig ricyp) mee ase eee eee eee 100 
Figs. 4, 5. Natural size (after d’Orbigny’s figures) . 
6. Sutures enlarged, showing similarity to phylloceran outlines. 
GM COUOMOCERASNG MOSS OLN: Gls sly ci Lies se ae eee 100 
Figure of supposed Sphenodiscus requienianus d’Orb., showing coilopoceran suture. 
(After Grossouvre. ) 
WIGHSwrS Denod IsCcUsTKONINGcipely albu pee e sense se eee eae see eee eee 82 
Fig. 8. Suture natural size. Part of one suture is shown and this is continued by 
the auxiliaries of the next suture below. 
Near Maestricht; Senonian; DeKoninck Coll. Mus. Comp. Zool., Cambridge. 
276 
