INTRODUCTION. xill 
3. Genus ACANTHOCYATHUS. 
Milne Edw. and J. Haime, loc. cit., p. 292, 1848. 
Corallum simple, free, subturbinate, slightly compressed, and subpedicellate. 
Calice more or less oval. Columella and pali as in Cyathma. Septa broad, exsert, and 
forming five cycla; systems unequally developed, so as to form sixteen groups. Coste 
partly armed with crests or spines. 
Typ. sp., Acanthocyathus Grayi, Milne Edw. and J. Haime, loc. cit., tab. ix, fig. 2. 
4. Genus BatHycYATHUS. 
Milne Edw. and J. Haime, loc. cit., p. 294, 1848. 
Corallum simple, adherent by a broad basis, tall, subturbinate, and slightly com- 
pressed. Calice subelliptical, with a broad and very deep fossula. Co/wmella small and 
crispate. Pali narrow, feeble, entire, and closely united to the septa. Sepéa exsert, thin, 
closely set, and forming apparently twelve equally developed systems ; five cycla, the last of 
which is more developed than the penultimate one, the septa of which are closely approxi- 
mated towards the wall, or even cemented to those of the primary, secondary, and ternary 
cycla. Coste very narrow, straight, unarmed, delicately granulated, and distinct down to 
the basis of the corallum. 
Typ. sp., Bathycyathus chilensis, Milne Edw. and J. Haime, loc. cit., tab. ix, fig. 5. 
5. Genus BRACHYCYATHUS. 
Milne Edw. and J. Haime, loc. cit., p. 295, 1848. 
Corallum simple, extremely short, widening very rapidly, and becoming free in the 
adult state. Calice circular, and very slightly excavated. Co/wmella very thick, fasciculate, 
and terminated by circular papilla. Pali very broad, entire. Septa exsert, narrow, and 
forming four cycla; the systems equally developed, and apparently twelve in number. 
Coste unarmed. 
Typ. sp., Brachycyathus Orbignyanus, Milne Edw. and J. Haime, loc. cit., tab. ix, fig. 6. 
6. Genus DiscocyatTuus. 
Milne Edw. and J. Haime, loc. cit., p. 296, 1848. 
Corallum simple, free, and discoidal. Ca/ice circular and slightly convex. Colwmella 
formed by a single vertical lamina; its apex smooth and undivided. Pai free and 
corresponding to the septa of the antepenultimate cyclum. Septa very exsert, broad, and 
striated laterally near their apex. Vail horizontal, and covered with an epitheca presenting 
some concentric stria. 
Typ. sp., Discocyathus Eudesii, Milne Edw. and J. Haime, loc. cit., tab. ix, fig. 7. 
