820 •• THETIS " SCIENTIFIC RESULTS. 



in the case described above) form a protection for the aggregated 

 gonangia and their contents. 



The dimensions of the specimens agree most closely witli those 

 of specimens recorded by Billard ([2], 1907, p. 179) as a variety 

 of the species. The wide range of variation to which the species 

 is liable, as the following measurements illustrate, renders unlikely 

 the supposition of Billard that his large variety may belong to a 

 new species. 



Dimensions. — 



Hydranth, length of adnate portion 0'28-0'51mm. 



>) >) >» tree ,, 



(primary hydrotheca) 0'21-0"33 ,, 

 ,, total length of free portion up to 0-52 ,, 

 ,, diameter at mouth 0'12-0'14 „ 



Localities. — Rare on Polyzoon from Station 44, off Coogee, 

 five to six miles from shore ; depth, 49-50 fathoms ; bottom, fine 

 sand ; 15th March, 1898. Abundant on bare axis of an Isid 

 Alcyonarian, and rare on the stem of Aglaophenia cruciulis from 

 Station 47, off" Bulge, six to eight and a half miles from shore ; 

 depth, 63 to 57 fathoms ; bottom, mud and abattoir refuse ; 16th 

 March, 1898. Rare specimens on Halicoi'naria furcata from 

 Station 48, off Wollongong, seven to eight miles from shore ; 

 depth, 55 to 56 fathoms; bottom, sand and mud to rock ; 18th 

 March, 1898. Station 54, within Jervis Bay; depth, 10 to 11 

 fathoms ; bottom, seaweed and sand ; 20th March; 1898 ; rare on 

 rhizoidal tubes oiDiphasia subcarinata. 



LAFOEA TENELLULA, Allman. 



(Plate Ixxxviii., fig. 5.) 



Lafo'ea tenellula, Allman, Mem. Mus. Comp. Zool. Harvard, v., 

 no. 2, 1877, p. 12, pi. viii., figs. 3, 4. 



Station 57. 



The specimens which I refer to this species are meandering 

 over the branches of a Hippothoa-like Polyzoon. They consist 

 of simple creeping stolons from which, at long, irregular intervals, 

 hydrothecse spring. The hydrothecse are very long, and are 

 almost cylindrical in shape, the cylinder, however, being slightly 

 bent at the middle. On one side of the base there is a slight 

 bulge, and it is generally towards this side that the upper por- 

 tion of the hydrotheca is inclined. The base of the hydrotheca 

 cavity is separated from that of the peduncle by an exceedingly 

 delicate diaphragm, the hydranth having been attached at this 



