115 
gorily tubular. The margin is surrounded by numerous 
°Qg and slender bristles, which are very commonly destroyed 
°® all but the distal rim, and very frequently are wholly 
!| e stroyed, from being so brittle; they may however generally 
he noticed as fragmentary tubercles. This species ap- 
Pfoacbes very closely to the L. nitida especially when the 
. frslles are destroyed. It differs however from that species, 
IP having the transverse bands so short as to extend only one- 
'°Urtb of the diameter, in having the aperture circular and 
■Grounded with bristles and having the cells contracted at 
® a ch extremity. 
^EPRALIA COCCINEA. Encrusting, calcareous; cells 
oval, rough, with a blunt process near the proximal lip 
°f the aperture. 
Eepralia coccinea, Johnston’s Brit. Zooph., p. 278. 
Sab. On rocks near low water mark. Talland sand bay j 
^°mhe Lansallosj Polperro ; Goran; Falmouth; Mount’s 
This generally occurs in circular encrusting patches of 
a,) ont one inch in diameter, but it sometimes covers a spaee 
°f an inch and three-quarters. It somewhat varies in colour 
^cording to the locality in which it grows ; it is most com- 
monly of a yellowish brown, or brownish flesh colour, fading 
? Cc asionally to a white. The cells are oval, and arranged 
® circular rows. Their surface is rough, granular or frosted, 
rJ'ich is more apparent in dried than in living specimens, 
**8 aperture is oval, plain, with a denticle near the proximal 
’ 1a rgin. As the cells lie on the crust in close approxi- 
mation and the apertures and denticles give it a waved ap- 
m-arance, the surface being granular, tbe line of demar- 
j i°n between the cells is very obscure, bence tbe whole 
C(! ms indistinct and confused. 
**• TRIDENTATA. Encrusting, calcareous ; cells oval, 
horizontal, rough; apertures oval, with a triangular den- 
l 'clo on tbe proximal, and one on each of the lateral 
ri ms. PI. xxii. fig. 5. 
^ flab. On rocks, stones, Ac., from deep water to low 
mark. Common. 
Ibis calcareous and encrusting species varies from one 
garter to one inch in diameter. In living specimens it is 
i t ? er al!y of a yellowish red colour inclining to a purple, but 
f ‘ s sometimes of a delicate flesh colour, all of which slightly 
death. The cells are oval, horizontal, and closely 
sj„ r ^ a 8 e d in circular rows ; they are rather indistinct at first 
aim ,roiu their Posted surfaces, their irregularity or waved 
'Pearauee about the apertures, and their being somewhat 
