110 



Dendronephthya nicobarensis, Henderson. 



The specimen is complete and measures about 4o cm. in height and 

 2 '6 cm. in greatest width. 



The stalk is thick and markedly ridged, and measures 1-4 cm. in length. 

 It gives off a number of thin-walled stolons from its base and is granular 

 in appearance and leathery in texture. 



The polyi)arium is nearly cylindrical in shape, bluntly rounded at the apex ; 

 it presents an unljroken, compact surface which all the polyps reach. The 



branching is not very profuse, and there is little 

 difference in the lengths of the various branches, 

 those about midway up the stalk being slightly longer 

 than the others. They break up into smaller branches 

 which in their turn divide and form the twigs on 

 which the polyps are borne. None of the branches 

 are flattened. 



The polyps are arranged in groups of five to 

 fourteen, and these again ai'e arranged in larger 

 groups. In the latter the surface is flat, or in a few 

 cases slightly concave. The polyps are low and round, 

 measuring from 0-32 to 48 mm. in height and from 

 48 to 064 mm. in breadth, and are placed at an 

 obtuse angle on stalks which may be very minute or 

 may reach a length of about 1 mm. The spicules 

 are arranged in eight double rows in each of which 

 there are five pairs of converging spicules. There are apparently two types 

 of polyps, one in which the spicules are large, and in which one or both of 

 the uppermost pair of spicules project, the other with slightly smaller spicules 

 and neither of the uppermost projecting. The spicules are spindles and average 

 in the smaller polyps about 019 mm. in length and 0-032 mm. in breadth, and 

 in the larger about 021 mm. in length and 003 mm. in breadth, while the 

 projecting spicules reach a length of 0'24 mm. 



The Stutzbundel shows the same peculiarity as in the other ilinhellata', 

 being well developed and containing one or more large spicules which project 

 beyond the polyp, or consisting of a nund^er of smaller spicules none of which 

 project. In the first case they measure as much as 22 mm. and project 0-8 

 mm. beyond the polyp, in the second case they average about Oit mm. in 

 length. 



Cortical spicules : {a) In the stem the spicules are spindles, either curved 

 or straight, three- and four-rayed, Y- and U-shaped forms, all of which are 

 covered with numerous blunt, thick spines. It is interesting to note that the 



Fig. 54. D. nicobareiisis. 



