EXPLANATION OF PLATE 45. 
71 
the circular lines on the surface of its horny mem- 
brane d, are lines of growth. (Original.) 
Fig. 3. Belemno-sepia from the Lias at Lyme, in the 
Oxford Museum j the Ink-bag is pi’eserved entire 
within the anterior conical sheath e. e. e. ; the 
greater part of this sheath is highly nacreous, in a 
few places (d.) it is horny. (Original.) 
Fig. 4. Large Ink-bag from the Lias at Lyme, in the 
collection of Mrs. Murchison, bearing on its surface 
undulating lines of growth similar to those on the 
surface of Fig. 1. The Ink is exposed at c. c. ; in 
other parts it is surrounded by the sheath, e. e. e. 
Nearly one-half of this sheath retains the appear- 
ance of horn, whilst the other half is highly na- 
creous. This interchange of condition, from horn 
to brilliant nacre, occurs in almost every specimen 
from the Lias at Lyme, in which the Ink-bag is 
accompanied only by the flexible anterior sheath, 
and the calcareous sheath has perished. (Ori- 
ginal.) 
Figs. 5. 6. 7. 8. Ink bags from the Lias at Lyme, par- 
tially surrounded by brilliant nacre. In no one of 
the specimens represented in PI. 44" is the least 
trace of the calcareous sheath of the Belemnite pre- 
served. See V. I. p. 376, Note. (Original.) 
Plate 45.» V. 1. p. 392 et seq. 
Fig. 1. Limulus Aniericanus (Leach), a young speci- 
men from Honduras, one third of nat. size. d'. 
Right compound Eye magnified, d". Two single 
* The following letters are applied in PI. 45 and PI. 46, to cor- 
responding parts of different animals. «. the shield; a', lateral 
portion of the shield ; b. the eye ; V. eye magnified ; h". frontal 
oyes ; c. tlie back ; d. the tail ; e. branchi®. 
