HYDROMEDUSAE 289 



the Stomach and in small horizontal folds; sometimes an indication of an interradial 

 horseshoe-fold near the base of the manubrium. Radial canals fairly narrow and with 

 smooth edges. Tentacles usually eight (four perradial and four interradial), eight 

 adradial bulbs without tentacles, and a variable number (up to sixteen) minute eradial 

 bulbs. Ocellus on the abaxial side of every tentacular bulb and of the adradial bulbs. 

 Colour: Manubrium, gonads, and basal bulbs pale yellow. Ocelli dark brown or reddish 

 brown (specimens in formalin). Size: Umbrella 9-10 mm. in height (including the 

 crown) and 7 mm. in width. 



Early stage: Umbrella broader than high, with a small, pointed crown. Manubrium 

 small, pyramidal, cross-shaped in transverse section; mouth with four small, but 

 distinct lips, not folded. Gonads not visible. Two opposite tentacles, the two other 

 perradial bulbs large, rounded, but without tentacles. Four very small interradial 

 bulbs. The four perradial bulbs each with an ocellus. Size: i mm. in height (including 

 crown) and i\ mm. in width (smallest specimen observed). 



The collection from 1898 to 1899 contains five specimens belonging to early and 

 intermediate stages (Plate XVI, fig. i ; Plate XIV, fig. 7) ; the full-grown adult stage not 

 present. The second collection, 190 1-2, contains numerous examples of all sizes. 

 According to Vallentin's notes the first was seen on 4 December, and several were 

 found on 16 December, but these are not preserved. Young specimens, 1-3 mm. 

 high, were frequently found between 8 January and 21 March, and adult, sexually 

 mature specimens between 22 February and 27 March. 



The umbrella has thin walls, and the umbrella cavity is broader than high. The 

 solid crown on the top of the umbrella is variable in shape ; as a rule it is a tall conical 

 process, like a spike on a helmet, but sometimes a broad truncated cone tending towards 

 a globular mass of jelly. In one specimen the umbrella measures 3 mm. in height and 

 4 mm. in width, and its crown is 3 mm. in height and 3 mm. in width; in the largest 

 specimen observed the umbrella is 5 mm. and the crown likewise 5 mm. high. 



The stomach in a transverse section is cross-shaped, having four perradial lobes, the 

 dorsal walls of which are attached to the subumbrella along the borders of a large 

 perradial cross, but there are no lateral mesenteries. On each side of the perradial lobes 

 the gonads form three horizontal folds. Specimens more than 5-5 mm. high are as a 

 rule sexually mature. 



The radial canals are fairly narrow and do not have a rugged edge, though they may 

 be slightly undulated in much contracted specimens. 



The tentacles are very long in some of the specimens, but the drawings show them 

 more or less contracted. They are covered with minute nematocysts. The basal bulbs 

 are large, and slightly laterally compressed, each having a large ocellus of a dark brown 

 or reddish brown colour, situated on a small projection with a flat top, close to the 

 exumbrella (Plate XVI, fig. 2). 



The numerous specimens of all sizes show the development of the tentacles. The full 

 number of marginal appendages in full-grown specimens is: eight tentacles (four 

 perradial and four interradial), each with an ocellus; eight adradial bulbs with ocelli; 



