R ADI ARIA. 31 



and Crustacea arc quickly dissolved in their stomachs. I he 

 organism of their stinging power is yet but imperfectly 

 understood, and the luminosity which many species possess 

 equally demands investigation. They are found in all seas, 

 and please the eye, both by their glassy transparency and by 

 their brilliant hues. 



To the different species of Acalcphoc, as to those of other 

 animals, whether inhabitants of the land or of the water, there 

 is allotted a certain range of geographical distribution. They 

 are known within certain boundaries, and beyond these they 

 are rarely found. Now and then, indeed, the winds and the 

 currents. bring to our shores marine animals, the inhabitants 

 of warmer climates; and such arc, of course, objects of 

 extreme interest to the naturalist. 



Some of these may here be mentioned, because they exem- 

 plify the great variety of aspect which species belonging to 

 the present division assume, and afford examples of some of 

 its most remarkable families. 



In 1838, an animal (Diphya clongata*) not previously 

 known as an inhabitant of European seas, was captured in 

 Belfast Bay. Its length was about an inch and a half, and 

 its transparency such that the eye could scarcely detect its 

 presence, when the creature was swimming about in a vessel 

 of sea-water. The most remarkable peculiarity in its structure 

 seems to be the facility with which it divides into two parts, 

 each of which continues to exercise powers of voluntary 

 motion, leading the spectator in doubt whether he is more 

 correct in saying, that it is one animal which easily separates 

 into two, or two animals usually found conjoined in one. ' 



Another inhabitant of the seas of warmer latitudes is the 

 Physalia, or Portuguese Man-of-war, fleets of which are some- 

 times wrecked upon our southern shores. It exhibits a crest 

 which rises above the surface of the sea, and is enriched with 

 tints of the richest blue and purple. 



Sometimes it happens that the sea of our northern shores 

 is enlivened by the mimic fleets of another navigator, the little 

 Velclla. On a bluish oval disc it exhibits a snowy, cartila- 

 ginous crest, fixed obliquely across, which has been compared to 

 the lateen-sail of the Malay boatmen. Thus propelled, the 



* Ilyndman in Annals of Nat. Hist. vol. vii. page 1G4. 

 PART i. C 



