APPENDIX. 
145 
Order IT. CORNEA. 
The polypes covered with a horny flexible external case, forming 
a massive or arborescent polypidom, 
A. The body of the polype adnate to the cell. 
Earn. 2. Pedicellinid^, p. 93. 
Polypidom creeping, sending forth club-shaped cells ; tentacles 
numerous, contractile (not retractile) into the cells. 
B. The body of the polype separate from the parietes of the cell. 
Earn. 3. Vesiculariad^, p. 94. 
Polypidom confervoid, horny, fistulous, continued, not jointed; 
polype cell tubular, cylindrical, deciduous. 
Earn. 4. Cristatellid^, p. 99. 
Polypidom tubular, not jointed, often united together into a 
mass ; polype cells cylindrical, tubular, permanent. 
Earn. 5. Paludicellaid^, p. 102. 
The polypidom confervoid, jointed; polype cells ovate, with a 
roundish rather tubular lateral suhapical aperture, all opening 
on one side of the polypidom. 
c. The polypes covered ivith a coriaceous external case, which is 
thicker on the sides and underpart and thinner above j opening 
of the cell subapical, linear, transverse. 
Earn. 6. Elustrad^, p. 103. 
Polype cells placed side by side, forming an expanded crust on 
rocks, or continued frond, hearing cells on one or both of its 
sides ; ovicells numerous, subglohose. 
a. Interspaces between the cells coriaceous, 
1. Elustra, p. 103. 
Coral frondose, expanded, forked, with cells on both sides, or 
crustaceous, applied to marine bodies ; cells ovate, six-sided, 
broad above, narrower below, semi-alternate with scattered mar- 
ginal denticles ; ovarial cells globular. 
2. Chartella, p. 104. 
Coral frondose, expanded, lobed, with cells on both sides ; 
cells linear-oblong, in many series, with smooth edges. 
G 
