8 "endeavour" scientific kesults. 



One of the specimens of Aglaophenia megalocarpa had a colony 

 of this species over-running the stem. The hydrothecse however 

 differ from those of all other specimens which I have seen in 

 having the third (lowest) marginal tooth quite obsolete, so that 

 there is only a bidentate border. 



The usual condition of T). subcarinata is unbranched, but 

 branched specimens often occur. In such cases the branches 

 spring from normal internodes of the primary shoot, generally 

 below a hydrotheca, but in some cases above ; and the arrange- 

 ment of the hydrothecas in opposite pairs is the same on the 

 primary shoot as on the branches. 



In most specimens there is, inside the angle of flexure of the 

 hydrotheca, a slight transverse ridge or thickening, the rudiment 

 of that which in a more fully developed form is found in the 

 corresponding position in Sertularia crenata. 



hoc. : — Great. Australian Bight, 40 to 100 fathoms. 

 Genus Sertularia, Linn, (in part.) 



The Serf a! a r'ni' collected by the "Endeavour" — 8. macro- 

 carpa, 8. maplestonei, S. unguiculata — all belong to a well- 

 defined group, of which 8. elongata may be taken as the type, 

 and which includes also among Australian species 8. recta, 

 8. pulchella, S. geminata, Thuiaria heteromorpha, and possibly a 

 few others. 8. macrocarpa was placed by Schneider in his 

 " Dynamena-group," and 8. maplestonei and S. elongata in the 

 " Thuiaria-group,"though the tlvree species are identical in habit ; 

 and in neither case do the characters of these species conform to 

 the descriptions given by Schneider. 



In the Dynamena-group the hydrotheca 1 are opposite, with 

 only one pair on an internode, and the side branches, when 

 present, spring from one or both sides of a normal internode 

 The essential point is that the giving-off of branches does not in 

 any way disturb the order of the hydrotheca' on the primary 

 shoot, consequently the arrangement is precisely the same on the 

 stem and branches. Typical examples are S. gracilis, and 

 8. pumila, the first of which generally gives off its branches 

 singly, while in 8. pumila they are often in opposite pairs. 

 Dijjhnsia siibciirinuta is a common Australian example of this 

 — the most primitive — mode of branching. The ramification of 

 8. macrocarpa has no resemblance to this type, but, as 1 

 indicated in my original description, agrees precisely with that of 

 8. elongata and 8. maplestonei. The reference of these species 

 to the Thuiaria-group is equally untenable, as they do not bear 

 "from several to many" hydrothecse on each internode, but 

 Schneider fully recognised that the groups were not sharply 

 denned, and that many species were intermediate. 



