52 
EXPLANATION OP PLATE 31. 
D. Transverse section across the Ink bag. 
d. First or upper plate. This plate is very thin, and 
smooth, and its structure is obscure, except on the 
right marginal band at df, where the longitudinal 
ridges on its surface are very distinct. 
e. Upper surface of second plate, marked with broad 
wavy lines, passing on each side from the axis out- 
wards, across the body of the shaft, and over the 
marginal bands. 
f. Upper surface of a third plate, exhibiting minute 
curved striae, ascending symmetrically in opposite 
directions from each side of the axis of the shaft C, 
and descending towards its margin. These curved 
striffi are intersected by minute longitudinal straight 
lines, running nearly parallel to the axis of the 
shaft. Towards the apex of the shaft at/, the broad 
transverse curves predominate over the fine longitu- 
dinal fibres which lie beneath them. At g, no 
transverse curves are visible.* (Mrs. Buckland. 
Original.) 
Plate 31. V.I. p. 317. 
Fig. 1. Animal of Nautilus Pompilius, fixed in its shell- 
The shell is copied from one in the collection of Mr. 
W. I. Broderip. (Animal from Owen. Shell ori- 
ginal.) 
n. The Hood, or ligamento-muscular disk that surrounds 
the head. 
p. The digital tentacles protruded from their sheaths. 
k. Funnel. 
a. h. c. d. e. Siphuncle. The desiccated membrane of 
* Herman von Meyer (Palseologica, 1832, P. 322,) mentions the 
occurrence of ink bags, togetlier with the horny internal shells of 
Sepia, (Onychoteuthis) in the Lias of Culmbach and Banz. 
