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description or figure was ever published of this creature, and as the 

 diagnosis of the "Medusa'" to which Linnaeus applied the name of 

 *' cequorea " was too brief for identification, it is possible that some 

 one out of several Acalephse inhabiting otir seas might have been in- 

 tended. 



It is also possible, however, that a true JEquorea had been seen, 

 for there is a most beautiful species of this genus an inhabitant of the 

 Scottish seas. I met with it for the first time in August 1850, when 

 exploring the Minch (the channel between the outer Hebrides and 

 Skye) in company with Mr. MacAudrew and Prof. Goodsir, with the 

 advantages of the appliances for natural-history research with which 

 Mr. MacAndrew has furnished his yacht, the Naiad. As there is 

 neither figure nor description of any British JEquorea to be found, 

 and as considerable obscurity hangs around the Atlantic species of 

 the genus, I have drawn up the following notice. 



A number of individuals were observed : they were swimming near 

 the surface of the sea on a very calm and hot day : they varied in 

 size, from three inches in diameter to as much as half a foot or more : 

 they resembled broad shield-shaped discs of glass, slightly prominent 

 above, incurved at their sides and concave beneath: through the 

 discs were seen shining the pendent brown-tinged stomach, and around 

 it, like so many equal stripes or rays proceeding to the margin, the 

 linear violet genital glands : from the margin depended highly-con- 

 tractile violet tentacles. 



The umbrella is broad, shallow, and disc-shaped, its outline de- 

 scribing a gentle curve. It is hyaline, not very thick, and quite 

 smooth. The central portion of its interior, occupying about one- 

 fourth of its diameter, has dependent from it the membranous veil- 

 like walls of the stomach ; these hang not quite so low as on a line with 

 the margins of the umbrella. The stomach, although equal in width 

 throughout, may be divided into two regions, an upper and a lower. 

 The latter has a furbelowed and somewhat scalloped, but not cirrated 

 margin, and may be regarded as the mouth. The former is marked 

 internally by eight bands of transverse fibres, separated by as many 

 longitudinal ones ; these appear to be muscular. The whole of the 

 membrane of the stomach and lips is tinged with pale foxy brown, 

 partly disposed in streaks. Around the upper and inner margin of 

 the cavity are the orifices of the gastro-vascular canals ; these run, 

 without dividing or anastomosing, to the circular marginal canal of 

 the umbrella. In a specimen five inches across, they were 136 in 

 number. From the lower side of each canal depend two narrow, 

 rather wavy membranes of a violet colour, causing the ray-like streaks 

 that shine so conspicuously through the disc ; each of these arises 

 gradually near the superior extremity of a gastro-vascular canal, and 

 ceases abruptly at about one-eighth of the entire length of the canal 

 from the margin : they are the genital glands. At the junction of 

 each alternate gastro-vascular canal with the circular marginal one is 

 the bulb-like base of a marginal tentacle : these tentacles arise from 

 ovate bulbs and gradually taper to a fine point. The bulbs are pale. 



No. CCXXXVI. — Proceedings of the Zoological Society. 



