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Show 178 MESSRS. L. MURBACH AND C. SHEARER ON [June 16, PROBOSCIDACTYLA Brandt. 1. PROBOSCIDACTYLA BREVICIRRATA Haeckel (18, p. 160). Synonym P. filavicirrata A. Agassiz. Specific description.-The bell is a truncated oval, 7 m m . high by 6 m m . broad; the subumbrellar cavity occupies less than half this bell, leaving a clear thick mass of jelly forming the roof of the dome. Agassiz has well represented this in his figure in the N. A. Acalepha? (2, fig. 280, p. 173). The velum is quite narrow. The tentacles are short, and number in our largest specimen 54, being half as long again as the diameter of the bell. Small tentacle-bulbs bear the dark ocelli, and young tentacle-buds are seen between some of the older ones. Seen from the aboral side, an opaque cross marks the position of the four lobes of the stomach, on which a portion of the gonads rest. The lower portion of the stomach is more cylindrical, ending in the tubular much-folded mouth. This sometimes appears as four double folds, curved outwards and upwards. The gonads lie in the interradial folds of the stomach, and pass out along the unbranched portion of the radial canals. The radial canals branch twice dichotomously, and then somewhat more irregularly, so that there is finally a canal for each tentacle. Between the terminal branches of the radial canals are blind delicate canals running in eentripetally from the margin of the bell, reaching halfway up. These canals are on the exumbrellar surface, and do not appear to be hollow in section; the radial canals are nearer the subumbrellar surface. Nematocysts are seen scattered in clusters along these tubes at varying intervals, so that many masses of nematocysts may be found along the course of one tube. Colour.-The stomach is a dirty yellow. Agassiz (2) states that this Medusa is quite transparent. Whilst this is true of the upper part of the bell, the thick yellow mass of the stomach renders the lower portion quite opaque. Preservation in formalin seems to have caused considerable shrinkage : our measurements apply to preserved animals. Habitat.-Victoria Harbour, collected by Shearer; Pleasant Beach, collected by Kincaid. Discussion.-Nothing was seen answering to Agassiz's (2) description of the granular covering of the bell, except the patches of nematocysts already mentioned scattered here and there along the centripetal canals. Haeckel (18) has thrown doubt on the presence of nematocysts on these canals ; they are so well marked in all our examples that it seems strange he should have overlooked them. This Medusa was first found by Mertens on the coast of Kamchatka. Agassiz (2) reports it from the region of Puget Sound, but Haeckel considers Agassiz's species different from that of Mertens, naming it P. brevicirrata. These names are liable to give rise to some confusion. It is very doubtful if this |