28 EDWARD T. RROWNE. 



Eleithkria hodgsoni. 

 (Plate III., figs. 1-4.) 

 I h'scrlpt ion of the Species. — Umbrella nulimentary, and rcdiu-od to a nearly flat 

 circular disc, 1 ■ 5 to 2 mm. in tlinmeter. Velum very broad, covering the whole of 

 the under side of the umbrella. Stomach conical, partly projecting through the 

 aperture of the velum. Mouth small and circular. Radial canals eight in number 

 and very .short. Gonad.s surrounding the stomuch. Tentacles twenty to thirty-two, 

 each of which is bifurcated close to the basal end ; the upper arm beai-s five to six 

 pairs of lateral clusters of uematocysts and a terminal cluster ; the lower arm, 

 without clusters of nematocysts, terminates in an adhesive di.sc, or sucker. On the 

 under side of the basal portion of the tentacles is situated a thick pad of nematocysts, 

 and on the upper side, close to the ex-uml)rella, a conspicuous reddish-brown ocellus 

 is present. 



The ' Discovery ' collection contains six well-preserved specimens of this interesting 

 Medusa. They were tjiken on 20th February, 1902, ten days after the ship had taken 

 up her position for the winter, and a month before she was frozen in. 



The youngest specimen of the series is about 1 nmi. in diameter, with tlic gonads 

 just visible. It has eleven radial canals, and nineteen teuttxcles in various stages of 

 development, seven of which are tiny buds. The other .specimens are much older and 

 approach nearer to the adult stage. 



Xote-s on the Specimens. — The umbrella is rudimentary in the .sense that it has 

 completely lost its function as a swimming organ owing to the almost complete dis- 

 appearance of the umbrellar cavity. A reduction in the length of the uml)rella has 

 taken place, and this gives it the appearance of its being flattened out. The velum is 

 very broad and covers the whole of the lower side of the umbrella, and its aperture fits 

 tight round the conical stomach. In nearly all the specimens the velum is close 

 against the sub-umbrella, and in this position it is not at once recognised. The largest 

 specimen has its velum more expanded .ind curved outwards, .so tliat a space is clearly 

 visible between the velum and the wall of the sub-umbrella. This space represents the 

 umbrellar cavity, and is, I believe, used as a brood pouch for the development of the 

 ova up to the planula stage. 



The stomach has the shape of an inverted cone, and when expanded projects 

 through tlie aperture of the velum. At the apex of the cone is a .small circular mouth. 

 The radial canals (fig. 2) are variable in number. Three specimens have eight canals, 

 and three specimens have six, ten, and eleven cjinals respectively. The canals are very 

 .short, extending from the base of the stomuch, across the top of the sub-umbrella, to 

 the circular canal. According to Mr. Vallentin, the Falkland species has four radial canals. 



The gonads form a continuous ring round the stomach and are extended into 

 seven or eight swellings. Sections of one specimen show that each swelling contains a 

 large ovum, which is absorbing the small surrounding germinal cells. There are no 



