26 ANTHOZOA HYDROIDA. 



Mr. Stewart, whose work was published in 1802, tells us 

 that Sertularia pumila, " and probably many others, in some 

 particular states of the atmosphere, give out a phosphoric light 

 in the dark." If, he continues, a leaf of the Fucus serratus 

 " with the Sertularia upon it, receive a smart stroke with 

 a stick in the dark, the whole coralline is most beautifully 

 illuminated, every denticle seeming to be on fire."* Crabbe 

 appears to have witnessed the same phenomenon, for the 

 particularity of his description of it argues a personal know- 

 ledge;^ and my friend Dr. Neill, shortly after the publication 

 of the first edition of this History, wrote to inform me that 

 he had long been familiar with the fact. It was remarked 

 by Mr. Hassall, in 1840, to be more general than these 

 records would have warranted us to conclude, for he says that 

 he had then ascertained " that all the more transparent 

 zoophytes possess highly luminous properties. This fact,"" 

 Mr. Hassall continues, " I first discovered in a specimen of 

 Laomedea gelatinosa, and subsequently in a great variety of 

 other species. If a portion of it, adhering to the sea-weed 

 to which it is attached, be taken from the water and agitated, 

 a great number of bright phosphorescent sparks will be 

 emitted ; these sparks proceed from each of the denticles of 

 the coralline containing polypi, and the phenomenon is 

 equally apparent, whether the specimen be in or out of water." 

 " I lately had an opportunity of beholding this novel and in- 

 teresting sight of the phosphorescence of zoophytes to great 

 advantage, when on board one of the Devonshire trawling- 

 boats which frequent this coast. The trawl was raised at 

 midnight, and great quantities of corallines were entangled 

 in the meshes of the network, all shining like myriads of the 



* Elem. Nat. Hist. ii. p. 441. 



t " While thus with pleasing wonder you inspect 

 Treasures the vulgar in their scorn reject, 

 See as they float along th' entangled weeds, 

 Slowly approach, upborne on bladdery beads ; 

 Wait till they land, and you shall then behold 

 The fiery sparks those tangled fronds infold, 

 Myriads of living points ; th'unaided eye 

 Can but the fire, and not the form, descry." 



The Borough. Letter ix. 



