HYDROIDA. BALE. 285 



A small colony of this species was found growing on one 

 of the specimens of S. tasmanica. The longest shoots con- 

 sisted of seven or eight internodes. The hydrothecee are 

 seated high on the internodes, the tops of which reach only 

 to about their middle. The first internode is about as long 

 as the hydrotheca ; the more distal ones may attain more 

 than twice their length. Below the hydrothecse, and for a 

 distance equal to about the length of the latter, the inter- 

 nodes are narrowed downwards ; the rest of their length 

 is slender and of about uniform thickness, and for the most 

 part strongly undulated ; the undulations often extending 

 up nearly as far as the hydrotheca. 



The hydrothecse have no distinct annulations below the 

 shoulder, which is a somewhat prominent annular ridge, and 

 above which the hydrotheca is rather abruptly contracted, 

 but to a slight extent only ; between the shoulder and the 

 aperture is another annulation, which is of about the same 

 diameter as the expanded border. The width of the aperture 

 from point to point is very little less than that of the hydro- 

 theca at its thickest portion, a rather exceptional condition 

 among the quadridentate species. The emarginations of 

 the border do not usually run in a uniform curve from point 

 to point, but are somewhat flattened (as seen in profile), and 

 the teeth are more or less nipple-shaped. 



One of the shoots is continued into a stolon, and on this 

 are borne a new shoot and also two isolated single hydrothecae. 



Loc. Off South Cape, Tasmania, 75 fathoms. 



SERTTJLARELLA INDIVISA, Bale. 



Sertularella indivisa, Bale, Journ. Micro. Soc. Viet., ii., 1881, 

 p. 24, pi. xii., fig. 7 ; Id., Bale, Cat, Austr. Hydr. 

 Zooph., 1884, p. 105, pi. iii., fig. 5, pi. xix., fig. 27 ; 

 Id., Bale, Proc. Linn. Soc. N.S. Wales, (2), iii., 1888, 

 pp. 764, 765. Id., Marktanner-Turneretscher, Ann. 

 K. K. Hofmus. Wien, v., 1890, p. 224. Id., Billard, 

 Bull. Mus. d'Hist. nat., 1905, p. 334. 



Sertularella solidula, Bale, Journ. Micr. Soc. Viet., ii., 1881, 

 p. 24, pi. xii., fig. 8 ; Id., Bale, Cat. Austr. Hydr. 

 Zooph., 1884, p. 106, pi. iii., fig. 6, pi. xix., fig. 28 ; Id. f 

 Bale, Proc. Linn. Soc. N.S. Wales, (2), iii., 1888, pp. 764, 

 765. Id., Whitelegge in Etheridge, Mem. Austr. Mus., 

 ii., 1889, p. 41. Id., Hartlaub, Abh. Nat. Ver. Hamb., 

 xvi., 1900, pp. 71, 41, 56, 76, 125, pi. iv., figs. 3, 13, 14, 

 27, pi. vi., fig. 13 ; Id., Hartlaub, Zool. Jahrb., xiv., 

 1901, p. 371. Id., Stechow, Abh. math.-phys. 



