PLATE 17. 



Fig. 1. 89. 1. Ormoceras tentjifilum. (Pag. 55.) 



1. A fragment of this species, sliovving the siphon directly in contact with the ventral side of the shell, a 

 portion of which remains on the lower part of the specimen. There is also a slight irreguhuity in the 

 size of the annuUtions, which is a common occurrence. 



1 a. Transverse section of the last, showing tlie wrinkled inner surface of the siphon at the points of contrac- 

 tion. 



1 6. A longitudinal section passing through the siphuncle. The interior is here fdled with stony matter ; but 

 in other specimens, the inner surface of the t\ibe presents the same wrinkled appearance along the con- 

 tracted portions as is represented in 1 n. 



Fig. 2. 90. 2. Ormoceras tenuifilumI var. distans. (Pag. 58.) 



Fig. 3. 91. 3. Ormoceras? rracile. (Pag. 58.) 



Fig. 4. 92. 1. Endoceras subcentrau.. ( Pag. 59.) 



