848 " THETIS " SCIENTIFIC RESULTS. 



irregular intervals, the unfascicled stems of the colonies arise 

 reaching occasionally a height of 53 mm., and averaging between 

 30 and 40 mm. The stem is almost straight and generally bears 

 short, irregularly-set (never opposite) branches, which leave it at 

 a vi^ide angle, lie in one plane, and them.selves bear branclilets to 

 the second degree. It is built of very thick perisarc, and 

 although not divided into internodes vi'ith the regularity which 

 Bale suggests, it bears hydiothecpe, and is marked by occasional 

 deep constrictions. The branches, although, as a rule, they are 

 short and simple, occasionally reach a length of 20 mm., and bear 

 offshoots of seconrl degree. They arise from the stems at a point 

 proximal to a hydrotheca, and a little to one side. The branches 

 are not in general divided into regular internodes, but the inter- 

 thecal poi tions widen considerably from below upwards so that 

 each hydiotheca appears to rest on a bracket. 



From one to four hydrothecse occur between successive nodes, 

 but they are not separated by equal distances, for, almost a 

 millimetre apart at one place, at another they are so close that 

 the base of one is opposite the adnate portion of its predef-essor. 

 The hydrothecse are '• large, stout, cylindrical, smooth, usually 

 somewhat rounded at the base, curved outwards," and in all 

 respects a^^ree with Bale's figure and desciiption, except as 

 regaids the proportion attached to the internode. In Bale's 

 specimens, thpy are " adnate nearly half their height," while in 

 the present specimens only one-third of the total height is 

 attached. This is due chiefly to the greater length of the free 

 portion, the actual length attached being almost equal in both 

 cases. I refer again to the great tenuity and delicacy of the 

 walls of the hydrothecse and to their consequent poor state of 

 preservation. 



Gonosome. — Not present. 



Dimensions. — 



Hydrorhiza, diameter 0*38 mm. 



Stem, diameter... up to 039 mm. 



Hydrotheca, total length^s 0-80-0-84 mm. 



,, length adnate ^ 0-27-0-32mm. 



,, diameter at mouth 0*32 mm. 



Distance between corresponding points of 



successive hydrothecse 0"26-0'98 mm. 



The above measurements agree closely with those deduced from 

 Bale's figure, but they are very much larger than those of the 

 examples I have recorded from the iNIergui Archipelago as Sertu- 



3 8 Primary hydrothecse were measured ; the rim of a secondary hydro- - 

 theca may increase the length by about 0"1 mm. 



