A cross section of the stem shows a moderately thick coenenchyma, a series of smal! but 

 well-defined watervascular canals, and an axis with a proportionally large white central core. 



Spicules. rhese are all small, but of several types. Regular, ten-te spindles with 

 nilarly disposed, very prominent verrucae are common. There are also many doublé clubs 

 such ;b 1\ tlls "laminatoclavate" spicules 1 , with a marked constriction around the middle. 



A number <>( crosses an- also found, the arms of the crosses being tumid and densely 

 tuberculate, forming a four-leaved rosette. While the coenenchyma is divided into two layers 

 by the watervascular system, 1 tan not determine any constant difference between the spicules 

 of these laj 



r. The colony in alcohol is very light buffy brown. The axis is dark brown and 

 spicules colorless. 



o. Plexaura flava new species. (Plate II, figs. i, \a-, Plate IV, fig. 6). 



St.it. ui. Bay of Labuan Trini;. West coast of Lombok. iS — 27 meters. 



Stat. 60. Haingsisi, Samau Island, Timor. Reef. 23 meters. 



Stat. 142. Anchorage off Laiwui, coast of Obi Major. 23 meters. 



Stat. 2y$. Anchorage off Pulu Jedan, Kast coast of Aru Islamls. 13 meters. 



A number of fragments of apparently more than one specimen were collected at Station 19. 

 The largest consists of a dense tuft of branches and branchlets. and is 37 cm. long. The main 

 stem is S mm. in diameter, and abruptly angulated 2.2 cm. from its base. After giving off 

 one compound, and a number of simple branches, it divides into two approximately equal parts 

 12.5 cm. from its base. These branches give off numerous compound and simple branchlets. On 

 their proximal portions both the main branches and their compound offshoots give off terminal 

 twigs from all sides. On their (listal portions they give off usually simple twigs with a strong 

 tendency to a regularly pinnate arrangement, although occasional twigs are given off from both 

 the front and back of the distal parts of the colony. The pinnae are about 4 mm. apart, on 

 the average, and about 1.5 mm. in diameter. The main stem is rlattened, but the branches 

 are round. The calyces are rather more prominent than in most species of this genus, and are 

 distributed on all sides of the branches, with a tendency to be more crowded on the sides 

 than on the front and back. 



The individual calyces show externally as very low verrucae. The aperture is often 



mpletely closed by the contraction of the calyx margin. The polyps are completely retractile, 



but the tentacles do not sink below the level of the polyp walls. Thus there appears no Iobular 



margin around th<: calycular mouth, but the tentacles, in retraction, lie immediately below the 



margin. The tentacles are very deeply fringed. There are a few very minute, bar-like spicules 



the body walls and basal parts of the tentacles. 



A section of a branch shows a rather ill defined series of watervascular canals, 



is wholly corneous with a rather large central core which is white. 



f the I Monlhly Microscopical Journal, Feb. 1, 1870, p. 76, plate XI. II. figs. 38, 43. 



