50 MR JAMES RITCHIE : SUPPLEMENTARY REPORT ON 



cavity of the hydrotbeca proper from the small globular cavity at its base is a ring of 

 bright dots, indicating the points at which the base of the polyp was attached to the 

 hydrothecal wall. 



The gonosome is not present. 



Locality. On gulf weed from Station 537. Lat, 29 54' N., long. 34 10' W. 

 29th June 1904. 



Obelia geniculata (Linnaeus, 1758). 



In addition to the Gough Island locality given in the former report, this widely 

 distributed species occurs from another station. Gonophores are present on the colonies 

 from habitat (&). 



Locality. () Entrance to Saldanha Bay, Cape Colony. Depth, 25 fathoms. 21st 

 May 1904. (6) Growing plentifully, along with Plumularia lagenifera, var. septifera, 

 on the segments and telson of a lobster, Palinostus lalandii, from the same locality. 



Obelia hyalina, Clarke, 1879. 



Many small, 6-mm. high colonies of this species occur creeping over the fronds 

 of Saragassum weed in association with Gampanularia clytioides. The characters 

 are as described and figured by CLARKE, and the dimensions of our specimens 

 appear to agree more closely with those of the type than do the corresponding 

 measurements of the large-sized Talisman examples described by Dr A. BILLARD 

 (1907, p. 170). 



Measurements : 



Hydrotheca, depth . . . . 0'2 mm. 



maximum diameter . . . 0'18 ,, 



Peduncles, length ..... 0'36-0'45 mm. 



Stem internodes, length .... 0'54 mm. 



No gonangia were present. 



Locality. Creeping on gulf weed from Station 537. Lat. 29 54' N., long. 34 1 0' W. 

 29th June 1904. 



Obelia longissima (Pallas, 1766). 



In addition to the colonies already recorded from the South Orkney Islands, a small 

 fragment whose characters agree with those of the above species has been found at Gough 

 Island. 



Measurements : 



Hydrotheca, depth ..... 0'38-0'45 mm. 



,, diameter at margin . . . 0'38-0'45 ,, 



Locality. Off Gough Island. Depth, 25 fathoms. Bottom, rock. 23rd April 

 1904. 



(ROY. soc. EDIN. TRANS., VOL. XLVII., 72.) 



