Messrs. M'Andrew & Forbes on new or rare British Animals. 391 



ArmB lanceolate, furbelowed and winged, separated from each 

 other nearly to their bases. Their more solid and central parts 

 are dotted with orange spots ; their membranous margins are 

 tinged with rose-colour : a canal perforates their united bases 

 and opens into the central cavity. 



This Medusa is highly phosphorescent ; when irritated in the 

 water by night it seemed like a globe of fire. The phospho- 

 rescence is of an intense light green, and proceeds from a mucus 

 which comes away by handling. It is given out chiefly and 

 most vividly by the warts of the skin — especially by the tri- 

 angular masses of them on the marginal lobes. The ovaries are 

 also phosphorescent, but require to be strongly irritated. If the 

 under surface of the umbrella be irritated, the warts on the ex- 

 ternal skin opposite give out light, but not the under surface 

 touched. A little crustacean is parasitic in the gastric cavity of 

 this Pelagia. When removed from its dwelling it rushed through 

 the water with rapid and frantic movements, seeking to return. 



The species appears to be Pelagia cyanella of Peron and Le- 

 sueur ; Medusa pelagia of Linnseus ; Dicencea cyanella of Lamarck. 

 The Pelagia denticulata of Peron and Lesueur and the Pelagia 

 parthenopensis of Lesson are scarcely even varieties of the same. 

 It is distinguished from Pelagia panopyra by the shortness of the 

 peduncle formed by the united bases of the arms. This character 

 appears however to be a variable one. It is a characteristic in- 

 habitant of the Lusitanian region of the North Atlantic, and ex- 

 tends into the Mediterranean. On the British coasts it is pro- 

 bably confined to the entrance of the Channel. 



The Pelagia noctiluca of Peron and Lesueur, founded on the 

 Medusa noctiluca of Forskal, is scarcely distinct. Forskal, in his 

 ' Fauna Arabica,*^ has the following pithy notes on its phospho- 

 rescence ; — '^ Hsec, si quse alia, vera est noctiluca. Multis expe- 

 rimentis in mari Mediterraneo, ubi habitat, prsesertim sub insula 

 Majorca institutis, mihi patuit, illam valde phosphoream esse ; 

 e margine lucem fortiorem emittet, quam e nucleo. [This is 

 true ; the warts which phosphoresce most strongly being very 

 small and few on the centre of the disc] Lacerata et in mare 

 projecta, lucida via ad fundum descendebant fragmina. Partes 

 discerptse, aquse marinse in vasculo mixtse et quassatse copiose 

 scintillant, et stagnando aquam cito corrumpunt. In cribello 

 aquam superfudi ; quae dum transibat, partes istse innumeris ra- 

 diabant stellulis : et ssepe affusa aqua, lumen non minuebant. 

 Id memorabile est, et magni canonis instar in hac experientia : 

 aquam marinam per chartam bibulam percolatam lucendi vim 

 perdere. Innumera Medusarum integrarum copia, ut corpora 

 undis attrita vel rupta, succumque gelatinosum efl*undentia toti- 

 dem certe phosphoros acceudunt : hinc tamen theoriam universa- 



