866 " THETIS " SCIENTIFIC RESULTS, 



Aglaophenia avicularis, Kirchenpauer, Abh. Nat. Ver. Hamburg, 

 v., 1872, p. 33, pis. i. and iii., fig. 3. 



Halicornopsis avicularis, Bale, Journ. Micro. Soc. Vict., ii., 1881, 

 p. 14, pi. xiii., tig. 3. Id., Bale, Cat. Austr. Hydroid Zoo- 

 phytes, 1884, p. 185, pi. X., figs. 1, 2, pi. xix., tig. 32. Id., 

 Bale, Trans. Roy. Soc. Vict., xxii., 1886, p. 101 (reprint 

 p. 29). Id., Marktanner-Turneretscher, Ann. K.K. Hofmus. 

 Wien, v., p. 279. 



Azygoplon rostratum, AWTdsin, Rep. Sci. Results "Challenger" 

 Exped., Zool., vii., 1883, p. 54, pi. xix., figs. 1-3. 



Halicornopsis elegans, Billard, Ann. sci. nat., Zool. (9), v., 1907, 

 p 323. Id., Billard, Ibid. (9), ix., 1909, p. 329. 



Stations 36 and 48. 



From a solitary locality come a few unfascicled fragments of 

 a specimen belonging to this, when fully developed, fascicled 

 species (c/. Kirchenpauer 1872, Bale 1886). While the descrip- 

 tions of Allman (1883) and Bale (1884), with their accompanying 

 characteristic figures, give account ol" the more salient features 

 of the species — Allman's figure of a colony portraying with 

 exactitude the very irregular mode of branching in our specimens 

 — a few details have to be added. 



A branch is set on a stout process which projects from the 

 proximal end of an internode of the parent shoot, and which 

 bears a whorl of three sarcothecse near its distal end. The first 

 branch-internode is longer than the remainder, and bears a single 

 longitudinal series of four or five sarcothecse on its adcauline 

 surface, and a single hydroclade near its distal end. The 

 remainder of the internodes are uniform, hearing two alternate 

 hydroclades (occasionally only one), the proximal adcauline, the 

 distal almost on the anterior surface of the internode. The base 

 of each hydroclade is accompanied by three (not two, as Bale 

 states, 1884, p. 186) sarcothecse; two small scoop-shaped indi- 

 viduals, one on the anterior proximal portion of the basal process, 

 the other on the internode, anterior and distal to the basal 

 process ; and the third, a larger canaliculate individual in the 

 distal angle between hydroclade and branch (see PI. Ixxxviii., 

 fig. 1). On long internodes, additional sarcothecse may appear 

 in the spaces between or beyond the hydroclades. 



The structure of the hydrotheca is even more bizarre than 

 authors have recorded. Although the coenosarc of the specimens 

 is in a very poor state of preservation, it was observed that the 

 position of the hydranth in the hydrotheca is peculiar. The 

 ccenosarc, instead of entering the hydrotheca at the base, proceeds 



