512 CLASS ECHINODERMATA. 
In each valley, from space to space, open some mouths, and 
the tentacula, instead of forming rosettes around these mouths, 
form a range along the sides of each valley. Some species 
have none at all, but the margin of each mouth is merely 
festooned. (Madr. labyrinthica, Sol. et Ell., &c.) 
If the hillocks which separate these vales, are raised in 
leaflets, or crests furrowed on both sides, the species are 
PavoniA. There are mouths in the bottom of the valleys, 
and usually without tentacula. (Madr. agaricites.) 
When these hillocks are elevated in cones, as if they were 
salient stars, M. Fischer names them HyDNoPHORA, M. 
Lamarck, MONTICULARIA. They should be distinguished 
according as their polypi are at the summit of the salient 
part, as in the oculine, or in the bottom of the concave parts, 
as in the meandrine. (Madr. exesa., Sol. et Ell.) 
AGARICINA, 
Are composed of laminz, hollowed on one side-only, by 
valleys which are themselves furrowed. (Madr. cucullata, 
Sol. et Ell.) : 
It has been thought that we might approximate to the 
madrepores in general, certain polyparie ; SARCINULA, Lam., 
formed of cylinders, whose section forms a star, in conse- 
quence of the projecting lamina, which traverse the interior, 
Madr. organum, Lin.; when there is a solid axis in the 
middle of the lamine, these are SryLIN&Z. These polyparie 
may also, perhaps, be related to the tubipora. 
MILLEPORA, L., 
Have their stony part of very various forms, and its surface 
only hollowed with small holes, or pores, or even without any 
apparent holes. 
M. Lamarck distinguishes 
