Dendy. — On Virgularia gracillima. 2o7 



the rhachis, with the typical well-developed radiating fibres. 

 Length of the whole fragment, 77"5mm. 



"Habitat. — Station 167a, Queen Charlotte Sound, near 

 Long Island, New Zealand. Depth, 10 fathoms. Mud. June 

 27, 1874." 



All the specimens obtained from Lyttelton Harbour are 

 smaller than the " Challenger" fragment, the largest, which, 

 however, is imperfect above and below, measuring only 60mm. 

 in length. Fortunately, however, one specimen is quite per- 

 fect, a condition very unusual in Virgularia. This specimen 

 is 45mm. long. The length of the rhachis, or polyp-bearing 

 upper portion, is about twice that of the stalk, or lower portion 

 without polyps, although it is difiicult to say exactly where 

 the stalk ends and the rhachis begins, as the lowest polyps ar& 

 merely minute buds. Both stalk and rachis are straight. 

 The stalk is about 1mm. thick in the middle, and ends below 

 in a thin-walled oval bulb. The greatest diameter of the 

 rhachis, together with the pinnules, is l-5mm. 



Most of the pinnules contain four polyps, but the number 

 varies somewhat, especially in some specimens. In the 

 middle and upper parts of the rhachis the pinnules alternate 

 with one another and overlap in pairs on the dorsal aspect. 

 In the lowest part of the rhachis, where the polyps are first 

 appearing as close-set transverse rows of minute buds, the 

 young pinnules thus formed are opposite to one another. At 

 the apex of the rachis the pinnules become smaller and the 

 polyps fewer until they are finally represented by a few 

 minute warts. 



The slender calcareous axis is very sharply recurved at its 

 lower end, and runs up again through the stalk for a little 

 distance nearly parallel with its former course, thus forming 

 an obhque loop, which is filled by a thin fibrous membrane 

 stretched between the descending and ascending limbs. In a 

 specimen dissected the lowest part of the loop was placed at a 

 considerable distance from the end of the stalk, the bulbous 

 dilatation lying below it. 

 There are no spicules. 



The living colony is nearly colourless. Spirit specimens 

 show a rather conspicuous longitudinal groove along the 

 ventral surface of the rhachis. 



17 



