808 MR. J. RITCHIE OX iiYDROiDs [May 24, 



cylindrical neck, the bn.^e of which is attached to the hydrotheca 

 at the chitinous projections alrejidy descrihed. Distally thi.s 

 swells out into a very definite l)ull), which is surniounted hy a 

 circle of from 18 to 2U tentacles. At the bases of the tentacles a 

 )-ing of very lai-ge bean-shaped neniatocysts, 30 //, long by 6 {l 

 broad, surrounds the hydi-anth. Similar cells occur in the 

 coenosarc of hydrocaulus and stolon. 



Gonosome. — This does not appear to have been described. A 

 gonangium arises from the side of the hydrocaulus, about half-way 

 between the hydrotheca and the stolon. The female gonangium 

 is borne on a short stalk, and is loughly calceolate in shape, 

 resembling the female gonangium of //. heanii. except that here 

 the tubular orifice of the upper surface does not occur. All the 

 gonangia I have examined contain ova to the number of about 

 six. The male gonangium, therefore, remains unknown. 

 Dimensions : — 



Stolon, diameter 0'06-0"07 nmi. 



Hydrocaulus, length 0*18-0"28 mm. 



Hydrotheca, depth 0-024-0-027 mm. 



,, diameter at margin 0*08-0'10 mm. 



Gonangium, length 0'42-0'50 mm. 



,, greatest diameter 0'17-0'21 mm. 



Hydranth, length extended 1 "05 mm. 



,, „ contracted 0*78 mm. 



Locality. Epizoic on a polyzoon associated with Cori/deiHlriinn 

 sessile, from St. 35, between Warden Island, Howe Island, and 

 Lyall Island, 15 to 20 fathoms, rock and sand. 



Hitherto recorded only from Amboyna, in the Moluccas 

 (Pictet, 1893, p. 22), this record adds the species to the fauna of 

 Indian seas. 



Halecium tenellum Hincks (?), 1861. 



The trophosomes are lax in habit, and in all other respects 

 agree with Hincks's species ; but, in the absence of the gonosome, 

 confident identification is impossible, especially since the likeness 

 between the trophosomes of young examples of the Australian 

 U. 2}(ii'viilum Bale and IT. tenellum appears to be almost perfect 

 (see Markt.-Turner., 1890, p. 218). 



Dimensions : — 



Stem, diameter 0*045 mm. 



Hydrotheca, depth 0-024-0-030 mm. 



,. diameter at margin 0'099-0"108 mm. 



The dimensions of the Mergui specimens are considerably 

 smaller than those of British examples. 



LocalUles. E|)izoic on Thyrosci/phus i^itieiisis from Stations 15 

 and 16, Kavenshaw Island, Sir John Malcolm Island, and Alligator 

 Hock, 5 to 18 fathoms, rock and sand, or rock and mud. 



Recorded with some doubt from Eastern Australia by Halo 

 (1884, p. 65) and Lendenfcld (1885, p. 405), this widely dis- 



