Smith.J ^^* [Oct. 2, 



Fig. 3. P. iowense, sutures. 



3 a. Sutures taken from the inner wliorl of 25 millimeters 



diameter. 

 3 b. Sutures on the outer Avhorl. 

 Fig. 4. Glyphioceras diadema Goklfuss, showing development of the 

 sutures (after Branco, Palceontographka, Vol. xxvii, PI. 

 ix, Fig. 1). 



4 a. First suture. 



4 b. Second suture. 



4 c. Third suture. 



4 d. At 1.25 millimetres diameter. 



4 e. At 2.25 millimetres. 

 4/. Adult. 



Fig. 5. Tornoceras retrorsum v. Buch (after Branco). 



5 a. First suture. 



5 b. Second suture. 



5 c. At 1.75 millimetres diameter. 



5 d. At 2.50 millimetres. 



5 e. At 10 millimetres, adult. 



Plate XX. 



Fig. 1. Gastrioceras, sp. indet 2(52 



1 a. Side view of a composite artificial cast, from three speci- 

 mens. 

 1 b. Side view of a septate fragment. 

 1 c. Cross section of whorl. 



1 d. Sutures. 



Fig. 2. Pronorites, sp 270 



2 a. Side view of septate fragment. 

 2 b. Cross section of whorl. 



2 c. Sutures. 



Plate XXI. 



Fig. 1. Endolohus missouviensis Swallow 252 



1. Side view of large specimen. 

 Fig. 2. Endolobns missouriensis Swallow. 



2 «. Side view of small specimen. 



2 b. Rear view of small specimen. 



2 c. Front view of small specimen, twice enlarged 

 Fig. 3. Endolobus missotii'iensis Swallow. 



3 a. Dorsal view, shewing internal lobe 

 3 6. Concave side of chamber. 



3 c. Convex side of chamber. 

 3 d. Chamber, from the side. 



