POLYZOA AND TUNICATA. 



237 



serpentine movements. The genus Pyrosoma contains ani- 

 mals aggregated in another manner. These are lengthened 

 Asoidiaus, united to each other so as to compose a long 

 free tube, open at one extremity and closed at the other. 

 This is also an oceanic genus, and is remarkable for being 

 vividly luminous, the light displaying the most gorgeous 

 and varied hues. We shall close this chapter with an 

 extract from Mr Bennet's u Wanderings," in which he 

 records his own observations of these interesting animals. 



" On the 8th of June, being then in lat. 0° 30' south, 

 and long. 27° 5' west . . . ]ate at night, the mate of 

 the watch came and called me to witness a very unusual 

 appearance in the water, which he, on first seeing it, con- 

 sidered to be breakers. On arriving upon the deck, this 

 was found to be a very broad and extensive sheet of phos- 

 phorescence, extending in a direction from east to west, 

 as far as the eye could reach. The luminosity was con- 

 fined to the range of animals in this shoal, for there was 

 no similar light in any other direction. I immediately 

 cast the to wing-net - over the stern of the ship, as we ap- 

 proached near the luminous streak, to ascertain the cause 

 of this extraordinary and so limited phenomenon. The 

 ship soon cleaved through the brilliant mass, from which, 

 by the disturbance, strong flashes of light were emitted, 

 and the shoal, judging from the time the vessel took in 

 passing through the mass, may have been a mile in 

 breadth. The passage of the vessel through them, in- 

 creased the light around to a far stronger degree, illumi- 

 nating the ship. On taking in the towing-net, it was 

 found half filled with Pyrosoma (Atlanticumi), which shone 

 with a beautiful pale-greenish light, and there were also 



