182 MESSRS. L. MURBACH AND C. SHEARER ON [June 16, 



tentacle-bulbs of Zygodactyla cyanea, which are not true excretoiy 

 papillte in which an opening is present, but probably simple 

 tentacle-buds or spurs. Agassiz (2) has described similar structures 

 in a number of ^quorids, as lihegmatodes tenuis, Zygodactyla 

 grcenlandlca, JEqtwrea alhida. Possibly in some cases these may 

 be the true excretoiy papillae which he has seen but misunder- 

 stood, or they may be simple tentacle-spurs, and so entu-ely 

 different sti'uctures ; his desciiptions and figures do not make this 

 clear : if they are excretoiy jOfipiUfe he does not i-ecognize their 

 structure and proper position. Milne-Edwards (30) speaks of 

 tubercles on the bell-margin of JEquorea violacea, " ayant la foniie 

 d'un petit mamelon" (pi. i. fig. 1 c, d), which may be these ex- 

 cretory papillfe, but here, again, their structui'e is not recognised. 

 It is to Metschnikoff (31) that we are indebted for the first 

 correct descrijition of these structures ; he was the first to recognise 

 their position under the velum, the opening in the apex, and 

 their connection with the circular canal. His figures are by far 

 the best, although fig. 2, pi. v., is open to the same objection as 

 Haeckel's figui'e ; fig. 7 is, however, veiy plain. 



In M. victoria these structures seem to have a very regular 

 arrangement, one opposite each tentacle-bulb and one in the 

 middle of the space between consecutive tentacles. In Plate XXII. 

 fig. 2 is represented a section passing through the beU- margin 

 in the plane of one of these papillse ; the opening in the apex is 

 distinct, being connected with the circular canal by a passage 

 lined with strong cilia. These papillae do not seem to be present 

 in young specimens, only the la,rger and older examples appear 

 to possess them. It is doubtful if their function is purely 

 excretory. Brandt (6, pi. v. fig. 4) shows the continuation of 

 the radial canals into the mouth- lobes of his Mesonema {Zygo- 

 dactyla) ccertdescens, similar to their continuation into the mouth- 

 lobes of 31. victoria, as already described. He also shows a 

 peculiar rectangular communication of these canals, on the 

 mouth-lobes, which is not present in our species. "While col- 

 lecting olf the inlet of Victoria Harbour early in July, on several 

 occasions lens-shaped masses were picked up, they Avere about 

 3 cm. broad ; towards the end of the month, when this Medusa 

 was obtained, they proved to be the central gastric peduncle from 

 which the peripheral parts had been worn and macerated away, 

 leaving a hard, smooth, lens-shaped mass. Fewkes has well de- 

 scribed these from M. cyaneum as " . . . . flat, slightly convex 

 above, rounded convex below." He regards them as probably 

 homologous with the gelatinous peduncle of genera like Liroj^e, 

 Geryonia, and Garmarina. M. victoria frequently contracts the 

 bell when disturbed in a characteristic manner, the thin flexible 

 margin being folded in, the tentacles almost rolled under the 

 velum, the gastric peduncle making a rounded protuberance on 

 the upper surface of the bell. Huxley (23, pi. xxxvii. fig. 11) 

 bhows this attitude in his drawing of Oceania ? Although the 



