26 



sides of the coral. The branches do not exceed 10 mm. in length ; they do not branch much, 

 when they do it is often dichotomous; the diameter at the base of a terminal branch is 1,2 mm. 

 The colour is white, the surface smooth except for the usual pits made by the terminations 

 of the canals which are irregularly scattered on the main stem and arranged so as to form 

 longitudinal striations on the younger branches. The cyclosystems have a diameter of 1,2 mm. 

 They are round or irregular in shape. The ampullae occur as swellings round the base of the 

 cyclosystem. Male ampullae only were found (Fig. 34 and 35). 



This species is closely allied to C. tenuis, the chief difference being the larger size and 

 stouter growth of the colony of C. major and the larger size of its cyclosystems. 



The species may be defined : 



Hydrophytum not flabellate, 30 mm. in height; main stem stout, hollow, fistulose and 

 coalescing, inhabited by a polychaet worm; cyclosystems 1,2 mm. in diameter; ampullae as 

 swellings round the cyclosystems. 



Steganopora gen. nov. 



Plate III, figs. 36, 17 and 38. 



This genus differs greatly from all other genera of the Stylasteridae in having the zooids, 

 both gastrozooids and dactylozooids, in very close communication by short, broad canals. In other 

 Stylasterids, the only connexion which exists between the zooids is the coenosarcal net-work of 

 canals. Conopora, however, is a partial exception, the dactylozooids being closely connected with 

 the gastrozooid by short broad canals. The gastrozooids and dactylozooids in Steganopora are 

 very long and penetrate very far down the stem (Fig. 38). In consequence of the close proximity 

 of the zooids, each zooid has not a separate and distinct pore ; there is no true base to it and 

 consequently there are no styles. The gastropores are without a scale and lie concealed among 

 the long, tubular dactylopores, which give the surface a very spiny appearance. A spadix is 

 present in the male gonophore. There are several gonophores in each ampulla. 



1. Steganopora spinosa sp. n. Plate III, figs. 36, 37 and 38. 

 Stat. 150. o°6'N., I29°7'.2E. Djilolo Passage. One fragment. 



Unfortunately only a very small fragment, 15 mm. in length, was obtained. There are no 

 side branches. The diameter of the base of the stem is 2,5 mm. The colour is white. The surface 

 of the coral, between the zooid pores appears smooth until it is calcined, when small irregularly 

 scattered pores of the coenenchym network appear. The gastropores are round or rather irregular 

 ia shape and about 0,3 mm. in diameter. The dactylozooids are numerous and irregularly placed. 

 They are situated in tubular pores which project upwards and outwards. They vary in size; the 

 largest are about 1,2 mm. in length. The ampullae occur all over the surface of the coral. 



Externally this species resembles Spinipora echinata (Moseley) but the likeness is only 

 superficial, the character of the canal system and dactylozooids being in no way similar. The 

 gastrozooids of Steganopora also differ from those of Spinipora in having no style. 



