260 ThompsorCs Zoological Researches, 



voyager under the appearance of thick bars of metal of about 

 half a foot in length, ignited to whiteness, scattered over the 

 surface of the ocean, some rising up and continuing luminous 

 as long as they remain in view, while others decline and dis- 

 appear ; and the fifth variety is in distinct spots on the sur- 

 face, of great beauty and brilliancy. The light of the first 

 variety is more brilUant and condensed than that of any of the 

 others, and very much resembles, every way, the red gold and 

 silver rain of the pyrotechnist. It and the third kind are pro- 

 duced by myriads of various minute crustaceous animals, the 

 smaller Medusa and Mollusca, and, perhaps, some Annelides ; 

 the second appears to proceed from the gelatinous Medusa of 

 a large size; the Pyrosomae (of which we have figured a spe- 

 cies in Vol. III. p. 534.) are the cause of the fourth kind, which 

 may often be witnessed by vessels bound to India or the east-* 

 ward of the Cape of Good Hope, occurring in the calm lati- 

 tudes near to the line. The Sapphirina indicator, an insect 

 somewhat resembling in appearance thewoodlouse (Oniscus)^ 

 and about one third of an inch in length, emits the last variety 

 enumerated, which appears to be limited to the seas situated 

 to the north and west of a line drawn from the Cape of Good 

 Hope to the southern extremity of the Island of Ceylon. AH 

 these heads Mr. Thompson has illustrated with a detail of 

 very interesting facts, drawn from the writings of travellers 

 and from personal observation ; and at the end of his elabo- 

 rate memoir he describes some previously unknown luminous 

 animals of the same family as the opossum shrimp, and much 

 like it in general appearance. 



We conclude this imperfect notice of these Researches by 

 an earnest appeal on their behalf to our zoological readers ; 

 for, in our opinion, they are indispensable to such of them as 

 are practically engaged in the study of the invertebrate tribes. 

 To Mr. Thompson himself we would say a word, soliciting 

 some greater attention to his language ; the sense of which is 

 occasionally obscured by slight inaccuracies in grammar (pro- 

 ceeding from inadvertency), and by a carelessness in punctu- 

 ation which is inexcusable. We will, moreover, recommend 

 it to him to consider, whether it is not akin to quackery for 

 an author to endeavour to arrest attention by marks of won- 

 der (I !), and by continual boasts of the importance of his own 

 discoveries. The value of these it would be better to leave 

 to the sense and judgment of his readers. 



