254 " ENDEAVOUR " SCIENTIFIC RESULTS. 



Frankfurt-a-M., 1897, p. 307. Id., Levinsen, Videsisk. 

 Medd. fra den naturh. Foren, 64, 1913, p. 285, pi. v., 

 figs. 16, 17. 



Hebella cylindrica (in part), Pictet, Rev. Suisse Zool., i., 

 1893, p. 41. 



Hebella scandens (in part), Bale, Proc. Roy. Soc. Viet., 

 (n.s.), xxvi., 1913, p. 117. 



Not Lafoea cylindrica, von Lendenfeld, Proc. Linn. Soc' 

 N.S. Wales, ix., 1884, p. 912, pi. xl., figs. 4-5. 



(See also, under H. calcarata, references to Billard and 

 Ritchie, who rank H. contorta as a synomyn of H. 

 calcarata). 



There is room for a difference of opinion as to whether 

 H. contorta, which is distinguished from H. calcarata by the 

 smaller size and somewhat twisted form of the hydrothecse, 

 should be regarded as a distinct species. My specimens do 

 not fully agree with Marktanner-Turneretscher's account, 

 the hydrothecse being only about .37-. 40 mm. in length as 

 against .46 mm., while the diameters are the same (about 

 .15 mm.); they are also rather less twisted (and in some 

 cases not at all). I have found them only on Sertularia 

 unguiculata, and the habit is peculiar, in that the main 

 creeping stolon, which runs up the rachis of the Sertularia, 

 bears no hydrothecse, but gives origin only to lateral branches, 

 which run along the pinnae of the host, and from which 

 spring the hydrothecse. Generally each pinna has its branch, 

 for so far as the Hebella extends, and it is curious to observe 

 how the stolon directs its growth from each pinna to the 

 next ; after giving off a branch to one pinna it grows 

 diagonally across the broad rachis of the host straight to 

 the base of the next, where it again branches, and so on in a 

 succession of zig-zags till it terminates, or till it assumes a 

 less regular course. Occasionally it divides into a number of 

 small stolons, which anastomose freely, forming a network. 

 The branches which run along the pinnae of the host are not 

 usually central, but seem to prefer the side, and although 

 the hydrothecse of the Sertularia are in opposite pairs, I have 

 not in any case seen those of the Hebella paired. Sometimes 

 an alternate disposition can be discerned, successive hydro- 

 thecse springing slightly to right and left on the slender stolon. 



Loc. — Ten miles north of Circular Head, Tasmania, on 

 Sertularia unguiculata. 



