75 



in latitude 12 N., and extending from W. long. 16 

 to 20. Toward the equator, a smaller species made 

 its appearance intermixed with the other, the light 

 " seemingly arranged in rings or whirls resembling a 

 gem studded with the diamond or opal." It did not 

 exceed an inch in length, and had seven or eight 

 rows of dots, and a somewhat contracted aperture. 

 These were in all probability either its ova or its 

 young. This last is the pyrosoma pygmcea * of Mr. 

 Thompson. 



Another kind of luminous appearance was observed 

 by Captain Horsburgh in the Arabian Sea. It some- 

 what resembled the oniscus, and was about one third 

 of an inch long. " During the time," he says, " that 

 any fluid remained in the animal, it shone brilliantly, 

 like the fire-fly." It was also found by Mr. Thompson 

 off the southern extremity of Madagascar, and again 

 on the Agullas banks near the Cape of Good Hope. 

 It is the sappharina indicator of Mr. T. f This crea- 

 ture is described as beautifully luminous by night, and 

 by day resembling the finest blue sapphire in colour, 

 with the opalescence of the adularia or precious opal. 

 By direct transmitted light, it resembled the fire stone 

 with tints of yellow, and by a less vivid and more 

 indirect light, assumed various intermingled tints of 

 orange, rose, blue, and green, possessed of a some- 

 what metallic splendour. Its geographical locality 

 appears to be limited to the seas situated to the N. and 

 W. of a line drawn from the Cape of Good Hope to the 

 southern extremity of Ceylon. 



Another phenomenon observed in violent storms at 

 sea makes its appearance in a luminous patch or ring 

 upon the masts and windward yard-arms, gradually 



* See Plate, fig. 7. t See Plate, fig. 6. 



E 2 



