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Show 1896.] BRITISH HYDROIDS AND MEDUSAE. 485 four radiating vessels, wdth a long, linear, somewhat clavate ovary, of a bright pink colour, commencing very near the centre, and terminating close to the margin in the course of each. Tbe stomach is very short, but wide, of a rose colour, and has four lanceolate, fimbriated lips, bordered by a compact edging of fibrous cells." Gosse's description differs slightly from that given by Forbes. His specimens appear to belong to a younger stage, about three-quarters of an inch in diameter, and with about fifty tentacles. N o mention, however, is made of the "minute epidermic hairs composed of fibrous cells " near the margin of the umbrella. The following is the description given by Gosse of the marginal vesicles :- "Besides these organs (tentacles), the margin is furnished with others They consist of cells, usually more or less globose, each containing one or more spherical bodies of high refra-cting power. Prof. Forbes has not noticed them in his description of this species ; they are, however, large and peculiar : first in shape, being semi-elhptical swellings of the substance of the marginal canal, and secondly in the number of their spherules. The spherules are arranged in a double crescentic row, those which form the middle being generally larger than those at the extremities. The capsules are eight in number, two in each quadrant, nearly equally distributed ; but not holding any fixed relation of position to the tentacles." The specimens which I took at Valencia have not only the cirri on the margin of the ex-umbrella ( = " minute epidermic hairs composed of fibrous cells ") as described by Forbes, but also the eight adradial marginal vesicles with numerous otoliths, as described by Gosse. The other details of the species agree with the description given by Forbes and Gosse. An early stage was taken at Valencia on M a y 4th. Umbrella bell-shaped, 2 m m . in length and width. Four perradial and four interradial tentacles; and also eight adradial bulbs, from which tentacles will develop in a later stage. A few cirri on the margin between the tentacles and bulbs, but none on the edge of the ex-umbrella. Eight marginal vesicles, each with 4 to 6 otoliths. The basal bulbs of the tentacles and the bulbs without tentacles are alike in coloration. There is a yellowish centre nearly surrounded by a deep purplish band, which does not meet on the inner side of the bulb. A specimen was taken 15 m m . in width and 11 m m . in length. Apparently ah the large watch-glass shaped medusae are in their earliest stages bell-shaped, the umbrella being about as long as wide. The umbrella gradually grows broader; the tentacles at the same time increase in number. A specimen was taken on April 23rd, at Valencia, with the umbrella 20 m m . in diameter and shaped like a deep watch-glass. The stomach short, and mouth with four fimbriated lips. O n the margin of the umbrella 28 large tentacles, and between every pair a large bulb, the commencement of another large tentacle. |
