152 



CORALS 



produce both male and female gonophores at the same time. 

 Only one case of hermaphroditism has been recorded in 

 Distichopora.^ The eggs are fertilised and undergo the 

 early stages of their development within the ampullae, and 

 when the female ampulla bursts, there emerges a free- 

 swimming planula larva. The Stylasterina are therefore 

 \'i\'iparous. 



DiSTiCHOPORA. — The genus Disticho- 

 pora, formerly known as red or violet 

 sugar coral (Rumphius) or Millepora 

 violacea (Pallas), forms a flattened, 

 fiabellate, and sparsely branched coral- 

 lum rarely exceeding 4 or 5 inches in 

 height and is almost invariably brightly 

 coloured (violet, red, orange, or brown). 

 The pores are situated on the edges of 

 the branches in three rows, a middle 

 row of gasteropores flanked on each 



t, -^. side by a row of dactylopores (Fig. 71). 



^ '-?" In some places the rows of pores pass 



on to the flat sides of the branches for 

 a short distance. The ampullae are 

 seen in clusters, sometimes on one only, 

 sometimes on both sides of the flat sur- 

 faces of the corallum (Fig. 70). When a 

 branch is examined in section, and for 

 this purpose a section made in the plane 

 of the pores is the best, each gasteropore 

 is seen to be provided with a long, 

 slender style. The pores have a long 

 curved course and penetrate almost to 

 the centre of the branch, but they are not, as a rule, 

 divided into partitions by tabulae. 



Distichopora may be found in rock pools and in shallow 

 sea water in the tropical regions of the old world and in the 

 West Indies. A few specimens have also been found in 

 deeper water in the West Indies (100-270 fathoms) and in 

 the Indian Ocean (150 fathoms). 



1 H. M. England, Trans. Linn. Soc. xii., 1909, p. 347. 



Fig. 71. — Distichopora. 

 'Edge view of a branch 

 showing the arrange- 

 ment of the gasteropores 

 in a median line ; the 

 dactylopores on each 

 side of them. On the left 

 may be seen a cluster of 

 ampullae. :■: 2 diams. 



