I>I.A.TE XI. 



Page. 

 Fig. 1. Trachyceras Judicaricum- '. 118 



1. A peripheral or ventral view of au imperfect specimen. 



1 a. A side view of same. 



Fig. 2. Trachyceras Judicaricum, var. subasperum 118 



2. A side view of an imperfect specimen. 



2 a. A peripheral or abdominal view of same. 



2 6. A view of the lobes and sinuses of the septa. 



Fig. 3. Trachyceras Whitneyi 116 



3. A peripheral or abdominal view of an imperfect specimen. 



3 a. Side view of same. 



Fig. 4. EcdiscocerasGabbi 128 



4. Side view of an imperfect specimen. 



4 a. A peripheral or abdominal view of same. 



Fig. 5. ACROCHORDISCERAS Hyatti 124 



5. Side view of a broken and somewhat distorted specimen. 



5 0. A side view of a larger imperfect specimen. 



Fig. 6. Gymnotoceras Blakei - 113 



6. Side view of a nearly complete adult specimen apparently of this species. 



6 a. A peripheral or abdominal view of same, showing the remarkable flattening of 



the periphery. 



Fig. 7. Arcestes? perplanus 120 



7. Side view of a cast, showing no surface-markings. 



7 a. A proiile view, showing the strongly-compressed form of the shell. 



