i 53 
(V) The mode of growth is within certain limits of some diagnostic value. 
Much branched forms must of course be noted, as also unbranched. Similarly anything 
markedly peculiar in the mode of branching, such as the constant down-drooping of the branches, 
seen in S. pendirfa , or the stout digitate processes of S', annectens , is of importance as a 
specific character. 
The actual number of branches and secondary branches, with a detailed measurement 
of their length, and of the distance of their origin from the base of the colony, seems to be 
of no great importance. 
(d) The number of canals present and also their position in the stem appear to be very variable. 
The nature of the walls, however, is a constant and definite character for a given species. 
(, e ). The “fan-like” or “chevron” pattern of the points is unimportant. 
Both types have been found on the same specimen by Thomson and Henderson, 1909. 
No example of fan-like arrangement has occurred in any of the twenty-three species of Siphono- 
gorgia or Chironephthya examined from the collection of the Siboga» Expedition. 
DESCRIPTION OF SPECIES. 
The following descriptions of species take account of (1) the nature of the anthocodial 
armature; (2) the nature of the verrucae, whether prominent or slightly developed, whether 
with a clear supporting bundle or not ; (3) the degree of retractility exhibited by the polyps ; 
(4) the character of the canals in the stem, whether large and irregular with relatively thin 
collapsible walls, or small and circular with very thick hard walls; (5) any unusual and distinc¬ 
tive feature of the spiculation, such as illustrated by S', obspicitlata Chalmers, and (6) any 
distinctive feature in the general mode of growth or in the coloration. 
o o 
LIST OF PREVIOUSLY DESCRIBED SPECIES WITH THEIR DIAGNOSTIC CHARACTERS. 
The arrangement is alphabetical. 
1. Siphonogorgia annectens Thomson and Simpson, 1909. 
(1) Crown — about 5 rows of spicules. 
Points —- 5 — 8 spicules arranged somewhat irregularly en chevron. 
(2) Verrucae very prominent, with openings directed upwards; closely set, so that the top of 
one is on the same level as the base of the next above it. 
(3) Anthocodiae wholly retractile. 
(4) Interior of stalk soft with few spicules; canal walls thick with distinctly gelatinous mesogloea. 
(5) Spicules bright red, often S-shaped, somewhat stout, with small compound warts closely packed. 
(6) Branching consists of stout digitiform processes. 
Colour — dull red. 
Locality: Puri Orissa Coast. 
2. Siphonogorgia anmilata (= Chironephthya annulata Harrison (1908)). 
(1) Crown — about 6 rows of spicules. 
Points — 3-5 spicules irregularly arranged en chevron, one generally larger than the others. 
SIBOGA-EXPEDITIE XIII d. 
20 
