OBSERVATIONS ON LUMINOUS ANIMALl. 3^B 



extremity of the process was divided into four tentacula, 



coYcred with little ctips or suckers, like those on ti^e>tefl> 



tacula of the cuttlefish. : -.r,^;- .fi?,..! 



This species of medusa bears a striking resemblance to Resembles 



the figures of the medusa hemispherica, published by Gro- '''*^^° "^ ^^°' 

 " r 7 1 y novius ana 



novius and Muller; indeed it diifers as little from these fi^ MuUer. 

 gar€S, as they do from each other. Its luminous property, 

 however, was not obiserved by these naturalists; which is 

 the more extraordinary, as Muiler examined it at night, 

 and says it is so transparent, that it can only be seen with 

 the light of a lamp. If it should be still considered as a 

 distinct species, or as a Tariety of the hemispherica, I 

 would propose to call it the medusa lucida. 



In this species, the central part and the spot round the Mode of Its 

 margin are commonly seen to shine on lifting the animaP^*"'"S- 

 out of the water into the air, presenting the appearance of 

 an illuminated wheel ; and when it is exposed to the usual 

 percussion of the water, the transparent parts of its body 

 are alone luminous. 



In the month of September 1805, I again visited Heme The?c animals 



Bay, and frequently had opportunities of witnessing the '^^'^'^^^^0'^ ^'^"'^ 



•" 1 / 11 "the surface of 



luminous appearance of the sea. I caught many of the the sea -when 



hemispherical and minute species of medusa, but not one*''","?'',°'^'^^^^» 



^ ' ' and d;d not 



of the beroe fulgens. I observed, that these luminous shine in day. 



animals always retreated from the surface of the water, as^'S^^- 



soon as the moon rose. I found also, that exposure to the 



day light took away their property of shining, which was 



revived by placing them for some time in a dark situation. 



In that season I had two opportunities of seeing an ex* Large flashes 



tended illumination of the sea, produced by the above ani- ^' ^',? ?u-!j? 

 ' * ■' sea Irom themr 



mals, TJje first night I saw this singular pfienomenon M'as -- — 



extremely dark, many of the medusa scintillans, and me^ 

 dusa hemispherica had been observed at low water, but on 

 the return of the tide, they had suddenly disappeared. On 

 looking towards the sea, I was astonished to perceivfl a 

 flash of light of about six yards broad, extend from the 

 shore, for apparently the distance of a mile and a half 

 along the surface of the Avater. The second time that I 

 saw this sort of light proceed from the sea, it did not take 

 the s^Hie farmj but was diffused over the surface of the 

 • ^ waves 



