PLATE 13. 
Fig. 1 . 86. 1 . Lituites undatus. (Pag. 52.) 
1. Lateral view of a specimen. A part of the last volution, near the aperture, is broken off. 
1 a. Lateral view of the cast of a smaller specimen t b. Dorsal view of the same. 
Fig. 2. 87. 1. Lituites convolvans? (Pag- 53.) 
2. A portion of a cast, showing the septa and part of the outer chamber. 
2 a. A vertical section of another individual as seen on the weathered surface of the limestone, showing the 
septa, which are removed from the smaller extremity by weathering. The cast is worn down below the 
siphuncle, which has not been observed in any specimen yet seen. 
Fig. 3. 86. 1. Lituites undatus. (Pag. 52.) 
A section apparently of this fossil, though the surface markings are not preserved. The septa are distinctly 
shown in a portion of the shell, and the dorsal siphon at two points a, a. 
