854 MANUAL OF THE MOLTUSGA. 
In the fry of Pnewmodermon the end of the body is encircled 
with ciliated bands. (Miller.) 
Distribution, 4 species. Atlantic, India, Pacific Ocean. 
Sub-genus? Spongiobranchea, D’Orbigny. S. Australis, Pl. 
XIV., Fig. 46. Gill (?) forming a spongy ring at the end 
of the body; tentacles each with 6 rather large suckers. Distri- 
bution, 2 species. South Atlantic (Fry of Pnewmodermon ?). 
Trichocyclus, Eschscholtz, T. Dumerilii, Pl. XTY., Fig. 48. 
Animal without acetabuliferous tentacles? mouth probosidi- 
form; front of the head surrounded with a circle of cilia, and 
two others round the body. 
? PELAGIA, Quoy and Gaimard. 
Etymology, Pelagus, the deep sea (not = Pelagia, Peron and 
Les.). 
Type, P. alba, Pl. XIV., Fig. 49. Amboyna. 
Animal fusiform, truncated in front, rough; neck slightly 
contracted ; fins small, fan-shaped. 
CymopocEA, D’Orbigny. 
Litymology, Kumodoke, a Nereid. 
Type, C. diaphana, Pl. XIV., Fig. 50. 
Animal fusiform, truncated in front, pointed behind; neck 
shghtly contracted; fins 2 on each side, first pair large and 
rounded, lower pair ligulate; foot elongated; mouth probosci- 
diform. 
Distribution, 1 species. Atlantic. 
CHAPTER III. 
CLASS IV.—BRACHIOPODA, Cuvier, 1805. 
(= Order Pallio-branchiata, Blainyille, Prodr. 1814.) 
THE Brachiopoda are bivalve shell-fish which differ from the 
ordinary mussels, cockles, &c., in being always cqual-sided, and 
never quite equivalve. Their forms are symmetrical, and so 
commonly resemble antique lamps, that they were called 
lampades, or ‘‘lamp-shells,” by the old naturalists (Meuschen, 
1787, Humphreys, 1797); the hole which in a lamp admits the 
wick serves in the lamp-shell for the passage of the pedicle by 
which it is attached to submarine objects.* 
* The principal modifications of external form presented by these shells are givenin 
Plato 15; the internal structure of each genus is illustrated in the woodcuts, which are 
