xxvi THE VOYAGE OF H.M.S. CHALLENGER. 



Subfamily Siphonogorgin^, 



Siphonogorgiacea, Kolliker, Festschr. phys.-med. Ges. Wurzburg, 1874, p. 22 ; Klunzinger, 

 Korall. des rothen Meeres, pt. i., 1877, p. 48. 



12. Paranejjhthya, Wright and Studer, Archiv f. Naturgesch., Jahrg. liii. Bd. 1, p. 20. 



The whole colony is upright and branched, and consists of a stem and branches. The 

 latter are again branched, and their terminal portions are covered over with the polyp- 

 heads, of which the tentacular portions are non-retractile. The canals of the stock are 

 narrow, numerous, and separated by partition-walls of relative thickness. There are 

 small foliaceous clubs in the polyps, in the cortical portions of the stem, and in the walls 

 of the canals. 



13. Scleronephthya, Wright and Studer, Archiv f. Naturgesch. , Jahrg. liii. Bd. 1, p. 20. 



The form of the colony and the nature of the canalicular system resemble the above, 

 but simple polyp-heads frequently occur scattered over the stem and branches. The 

 calyces are furnished with large spindle-shaped spicules, which also occur in the cortex. 



14. Chironei^hthya, Wright and Studer, Archiv f. Naturgesch., Jahrg. liii. Bd. 1, p. 20. 



The simple stem, which remains of uniform thickness throughout its course, gives oft' 

 terminally simple finger-shaped rigid branches. These bear isolated polyps at some 

 distance from one another, and but rarely give oft" secondary branches. Polyps and stem 

 are covered with large spindle-shaped spicules. Stem and branches are penetrated by 

 canals, the thick walls of which contain numerous spicules. 



15. Siphonogorgia, Kolliker, Festschr. phys.-med. Ges. Wurzburg, 1874, pp. 18-23 ; 



Klunzinger, Korall. des rothen Meeres, pt. i. p. 48, 1877. 



The colony is upright, branched ; on the branches and twigs the polyp-heads are 

 distributed or are terminal. The whole mesoderm of the axis and of the thick walls of 

 the canals is packed with numerous large spicules. The polyps are partially retractile. 



Family VIII. Helioporid^. 



Helioporidx, Moseley, Zool. Chall. Exp., vol. ii. pt. vii. pp. 102, 123. 



The compact corallum consists of a fibro-crystalline calcareous mass. This is 

 formed from a coenenchyma composed of numerous tubes, and from calyces with an 



