ALCYONARIA WHITBLEGGE. 315 



as opaque objects under the microscope, present an irregular len- 

 ticular appearance ; when seen by transmitted light they reveal 

 a very narrow smooth central constriction, an upper round disk, 

 minutely granulose and somewhat opaque, a lower irregular tuber- 

 culate disc, quite translucent and frequently larger than the upper. 



The granular disks of these modified double clubs are directed 

 outwards and form a fairly uniform crust over the whole colony. 



Situated immediately beneath this external layer are numerous 

 larger spicules, having a broad multilobate disk, and a very short 

 central boss surmounted by two or more tubercles. These spicules 

 exhibit a distinct central line of union, and the boss-like end is 

 directed outwards. 



The polyps are provided with a collar of curved spicules ; on 

 the lower dorsal surface of each tentacle are three curved spicules, a 

 short one placed transversely with the convex side directed towards 

 the summit, and two placed longitudinally with their convex sides 

 inwards. 



Embedded in the apices of the tentacles are a few short curved 

 spicules, with strong dentate processes on the convex side. 



(1.) The cortical spicules are rarely longer than broad. Size 

 03 by -03, -04 by -35 mm. 



(2.) Deep seated, broad, star-shaped, the rays and disk being 

 studded with warty tubercles. Size Diameter of disks from -05 

 to -2 mm., those measuring about -15 mm. being the most common. 

 The height is from -03 to '1 mm. 



(3.) The collar spicules are curved, sharp or blunt pointed 

 spindles with a few distant spines. Size -3 by -02, -35 by -03 mm. 



(4.) The tentacle spicules are slightly spinose, mostly on the 

 convex side, and frequently dentate at the apex. Size '1 by "02, 

 15 by -03 mm. 



Colour in formol is pale yellowish-white. 



This species differs from B. philippii in the smaller sizes of its 

 polyps, and from B. mollis in its spicular characters. 



MURICELLA PURPUREA, Sp. nOV. 



(Plate xvii., figs. 26-29.) 



The colony is erect, branched in one plane; it is 120 mm. in 

 height and 90 mm. in breadth. 



The main stem is straight in its lower two-thirds, the upper 

 third being a little curved ; it arises from an enlarged base and 

 gives off a series of short simple branches and about seven or 

 eight larger branches, which bear numerous branchlets, these in 

 turn bearing short, slightly flattened twigs. The larger and 



