Specres of ‘Challenger’ Reef-Corals. 295 
Sandalolitha dentata, n. sp. 
Corallum almost flat, irregularly sandal-shaped, fragile, 
translucent, being about 6 millim. thick except immediately 
around the mouth of the central calicle where the septa are 
somewhat elevated and thickened. The parent calicle attains 
a large size (nearly 15 centim. in length) before the smaller 
calicles begin to develop. Wall very thin, pierced with 
numerous small pores ; costa unequal, with very small granu- 
lated blunt spines, distinct, curving in radiating lines towards 
the short axis of the corallum except at the centre where the 
costal spines become crowded over a thickened circular space 
that seems to have been a former base of attachment. Septa 
of the central calicle of seven complete cycles, but incomplete 
orders are developed at the extremities of the long axis of as 
many as sixteen cycles; those of the first three cycles sub- 
equal, slightly thickened and prominent at the centre; and, 
with the exception of the very small ones, all the septa are 
nearly equally raised over the general surface, cut into 
strong long and narrow teeth, very granulated, especially at 
the apex of the teeth, which are divided into little points 
forming a blunt or pointed end. The septa of the higher 
orders unite one on each side with one of a lower order at 
that part of it from which they originate. 
Locality. ‘Tahiti. 
TICHOSERIS, nov. gen. 
Corallum compound, massive, columnar or lobate, with 
neither transverse calicinal ridges nor longitudinal crests, 
astreiform. Calicles with distinct solid walls, which are thin 
at their edges, but thick at their basal parts ; calicinal centres 
arranged either singly within their own wall, or united in more 
or less irregular and sinuous groups of two or more incom- 
pletely separated from each other and surrounded by the 
common wall of the calicle from which they are developed. 
New calicles arise either by direct fission of a single calicle 
forming two separate ones with distinctly raised walls, or by 
the upgrowth of the synapticula at different parts of the calicle 
to form new walls, the resulting centres often forming mean- 
droid series, until the development of their own wall isolates 
them. Septa not at all confluent, entire, those of adjoining 
calicles quite separated by the raised walls. Columella ab- 
sent or forming a very small styliform projection at the point 
of coalescence of the septa. Synapticula distant, very un- 
equally and irregularly developed, being generally rather 
thick interseptal outgrowths of the wall. 
