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shown externally.

a. a. a. Groves.

b. b. Alleys.

c. c. The lateral groves.

d. The intermediate one.

3. Inside of the same shell.

a. a. The dentated suture.

b. The middle ridge marked out on each
side into transverse pieces.

c. c. The alleys, with pores for the suckers.
d. One of the frames to which the jaws
are fixed.

4. Spines of Echinus cidaris.

a. Muscular fibres inserted in the base of

the spine, and surrounding the ball and 203-210 socket joint.

b. The muscular capsule laid open, and the

muscles attached to the base of the spine
turned back.

c. The origins of the muscles surrounding
the ball or tubercle.

d. One of the tubercles.

5. One of the suckers of E. esculentus.

a. The sucker; the pore in the centre is
supposed to be a spiracle connected
with the respiration of the animal.

b. The stalk of the sucker.

6. The suture of a portion of the alleys at the
lateral grove, in which the transverse
pieces are convex.


FIG. 7. The suture of a portion of the lateral grove
uniting with the above, in which the trans-
verse pieces are concave.

8. Suture of the intermediate grove divided at
the ridge (Fig. 3. b.). Teeth obtusan-

9. A circular space round the mouth, co-
vered with little oblong scales. In the
centre is the mouth with its five converg-
ing teeth.

10. Outside of one of the five pyramidal jaws,
in which the teeth are planted.

a. The jaw. b. The tooth.

11. Inside of ditto: a. the jaw, consisting in

ternally of two triangular transversely
furrowed, and probably molary plates.
12. A little bristle, terminating in a knob with
three awns, planted amongst the spines
on the shell, and, according to Cuvier,'
a species of Polype (Pedicellaria).
13. Another Pedicellaria? expanded like a
tripetalous blossom.

14. One of the spines of Echinus esculentus.


FIG. 1. Pentacrinus Asteria


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2. Portion of ditto, exhibiting the suckers on the

under side of the fingers


FIG. 1. Cinthia Momus

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