98 COELENTERATA—ANTHOZOA SUB-BRANCH II 
Arabia and the West Indies ; while outside the Alps in Europe and in America 
their distribution is mostly sporadic. In the Miocene and Pliocene the true 
coral-reefs retreat more and more towards the equator (Red Sea, Java, Japan), 
while the Hezxacoralla which persist in formations of the temperate zone 
(Vienna Basin, Italy, Touraine) constitute but an insignificant feature of the 
general fauna. 
Appendix to the Hexacoralla. 
Sub-Order C. TABULATA.' Milne-Edwards and Haime. 
Invariably composite coralla composed of tubiform or prismatic corallites. Walls 
thick, independently calcified, compact, or perforated by connecting mural pores. Septa 
but slightly developed (usually six or twelve), sometimes represented merely by vertical 
ridges or rows of spines, and sometimes entirely absent. Visceral chamber partitioned 
off into successive storeys by tabulae. Synapticulae and dissepiments wanting. 
To the Tabulata were originally assigned by Milne-Edwards and Haime all 
corals having numerous tabulae and rudimentary septa. Later researches have 
shown, however, that some of these forms (e.g. Pocilloporidae) belong to the 
Aporosa, others (Helioporidae) to the Octocoralla, and still others (Millepora) to 
the Hydrozoa ; while the affinities of a few (Chaetitidae, Monticuliporidae) are of 
such doubtful nature as to be referred by some authors to the Corals, and by 
others to the Bryozoans. The majority of the typical Yabulata (Favositidae, 
Syringoporidae, Halysitidae) exhibit close relationships to the Hezacoralla ; but 
since they are for the most part now extinct and are largely confined to the 
Palaeozoic rocks, the positive determination of their systematic position seems 
almost hopeless. The ontogeny of the corallites in the Zabulauta shows that the 
development of mural pores is homologous with the process of gemmation. 
Reproduction sometimes takes place by fission, but generally by means of buds 
from the edges of the calices at various stages during the growth of the parent 
corallites. Buds are given off early in Aulopora, producing basal corallites only ; 
periodically in Romingeria, producing verticils of corallites ; periodically and on 
one side in Halysites, producing linear series of adjacent corallites ; and very 
frequently in Favosites, ete., producing compact coralla with numerous mural 
pores representing aborted buds. 
Family 1. Favositidae. Milne-Edwards and Haime. 
Massive or branching coralla.  Covallites uniformly prismatic, tall, and united by 
their walls, which are perforated by large-sized pores. Septa very short, usually 
represented by but faintly projecting ridges or rows of spines, but seldom completely 
absent. Tabulae numerous, ‘situated at regular intervals, complete and horizontal, 
more rarely oblique or irregularly vesicular (‘cystoid’). ; 
The Favositidae are distinguished from the Poritidae, with which Verrill 
associates them, by their thick, solid walls, which are punctured by round, 
1 Lindstrém, G., Affinities of the Anthozoa Tabulata (Ann. Mag. Nat. Hist. Ser. 4, XVIIT.), 1876. 
—Dybowski, W., Die Chaetitiden der ostbaltischen Silurformation (Verh. der k. russ. min. Gesellsch. 
St. Petersburg), 1877.—Nicholson, H. A., On the Structure and Affinities of the Tabulate Corals of the 
Palaeozoic Period. London, 1879.—On the Structure and Affinities of the genus Monticulipora. 
London, 1881.—Roemer, F’., Lethaea Palaeozoica, I., 1883, p. 416.—Waagen, W., and Wentzel, W., 
The Salt Range Fossils. Palaeontol. Indica, 1887.—Haug, #., Ueber sogenannte Chaetetes aus 
mesozoischen Ablagerungen (Neues Jahrb. fiir Mineral.), 1883, I., p. 171.—Beecher, C. #., The 
Development of a Palaeozoic Poriferous Coral.—Symmetrical Cell Development in the Favositidae. 
(Trans. Conn. Acad. vol. VIII.), 1891. 
