30 



delicate, but of characteristic structure for this family, being formeel by a mere skeleton of 

 slender spindles. The collaret also is very delicate. The coenenchyma is packed with irregular 

 plates, many of which are of the same pattern as those in the calyx walls and usually of larger size. 



Spicules. By far the most numeróus and conspicuous spicules are of the unilateral 

 type characteristic of the genus, having one side edged with a row of thorn-like projections 

 which are lacking on the opposite side. There are also irregular plates, stars, multiradiate 

 forms. A few delicate spindles are found, usually forming the opercula. 



C o 1 o r. The colony is a decided greenish yellow, the axis dark brown and the spicules 

 yellow. The specimen from Station 105 is brighter yellow than the others. 



A specimen from Station 274 has much more slender branches than the one above 

 described, but is otherwise like it. 



4. Thesea immersa new species. (Plate VIII, figs. 4, 4^?; Plate XXI, fig. 4). 

 Stat. 289. 9°o'.3S., I2Ó°24'.5 E. Timor Sea. 112 meters. Mud, sand and shells. 



The type specimen in incomplete, and is apparently a branch of a much larger colony. 

 It is flabellate in form, rather straggling in habit, 14 cm. high and 15 cm broad. The main 

 stem, or branch, bifurcates 2.5 cm. from its proximal end, but these branches reunite by 

 anastomosis about 4.2 cm. above their origin. Above this they send off irregularly disposed 

 lateral branchlets which, in most cases, divide dichotomously. Two other cases of anastomosis 

 are seen in the colony. The calyces are quite regularly and evenly distributed on all sides of 

 the stem and branches. Being very low verrucje it is very difficult to teil where their walls 

 join the general surface of the ccenenchyma. They are about 1.9 mm. apart from summit 

 to summit. 



The individual calyces are exceedingly low verrucse, almost entirely immersed in the 

 ccenenchyma of the stem and branches, with nothing but the crown of points appearing above 

 the general level. The diameter of the margin is about 1.3 mm. The calyx walls are studded 

 with jagged triangular points and sometimes foliaceous projections from the unilateral spicules, 

 and the margin is surmounted by a crown of points. The verrucae are so low that the calyx 

 walls are insensibly blended with the general surface, which is itself studded with the same 

 angular projections. The polyps are completely retractile, but the calyx margin does not fold 

 over them. The operculum is thus exposed and is of the typical form, each flap being com- 

 posed of three slender spindles, two being much longer and more conspicuous than the third 

 which lies between their bases. 



Spicules. The typical unilateral forms, although numeróus, are not so abundant as 

 in the last species. The are also numeróus stars, crosses, multiradiate forms, etc, the stars 

 preponderating. There are a few true symmetrical spindles. 



Co lor. The colony, in alcohol, is pallid, almost white. The axis is brown and the 

 spicules colorless. 



