342 



OBSERVATIONS ON LUMINOUS ANIMALS. 



Another. 



Both mono- 

 culi. 



Luminous 

 ■vermes disco- 

 vered by the 

 author, 



ance the woodlouse, and was about one third of atii inch 

 in length. When viewed with the microscope, it seemed 

 to be formed by sections of a thin crustaceous substance. 

 J3uring the time that any fluid remained in the animal, it 

 shone brilliantly like the fire fly. • ' 



In the month of June in (he same year, he picked tip 

 another luminous insect on a sandy beach, which was also 

 covered with a thin shell, but it was gf a different shape, 

 and a larger size than the animal taken in the Arabian sea. 



By comparing the above description with an elegant pen 

 and ink drawing, which was made by Captain Horsburg, 

 and accompanied his paper, I have no doubt, that both 

 these insects nere monoculi; the first evidently belongs to 

 the genus limulus of Muller; I shall therefore beg leave 

 to distinguish it by the name of limulus noctilucus. 



My pursuits, and the state of my health, having fre- 

 quently led me to the coast, I have had many opportunities 

 of making observations upon the animals, vvhich illuminate 

 our own seas. Of these I have discovered three species: 

 one of which is a beroe not hitherto described by authors ; 

 another agrees so nearly with the medusa hemispherica, 

 that I conceive it to be the same, or at least a variety of 

 that species; the third is a minute species of medusa, 



^linute himi- 

 pous medusas 

 described. 



seen by navigators, although it has never been distinctly 

 examined or described. 



I first met with these auimals in the month of October 

 1804, at Heme Bay, a small watering place upon the 

 northern coast of Kent. Having observed the sea to be ex- 

 tremely luminous for several nights, I had a considerable 

 nquautity of the water taken up. When perfectly at rest, 

 |io light was emitted, but on the slightest agitation of the 

 vessel in which the water was contained, a brilliant scin. 

 tillation was perceived, particularly towards the surface; 

 and when the vessel was suddenly struck, a flash of light 

 issued from the top of the water, iii consequence of so 

 many points shining at the same moment. When any of 

 these sparkling points were removed from the water, they 

 no loljger yielded any light. They were so traitsparent, 

 -'^hW'ia'the air they appeared like globules of water. They 

 .->'■■-■ were 



