9^ THE DEPTHS OF THE SEA. [CHAP. in. 



In both of these last deep dredgings the dredge 

 brought up a large number of extremely beautiful 

 Polycystina, and some forms apparently intermediate 

 between Polycystina and Sponges, which will be 

 described shortly. These organisms did not seem to 

 be brought from the bottom, but appeared to be sifted 

 into the dredge on its way up. They were as numerous 

 adhering to the outside of the dredging-bag as within 

 it. During the soundings taken near this locality 

 quite a shower of several beautiful species of the 

 Polycystina and Acanthometrina fell upon the chart- 

 room skylight from the whole length of the sounding- 

 line while it was being hauled in. 



"We were now steaming slowly back towards the 

 coast of Ireland; and on Monday, July 26, we 

 dredged in depths varying from 557 to 584 fathoms 

 (Stations 39-41) in ooze, with a mixture of sand and 

 dead shells. In these dredgings we got one or two 

 very interesting alcyonarian zoophytes, and several 

 ophiurideans, including Ophiothrix fragilis, Amphiura 

 ballii, and Ophiacantha spinulosa. Many of the 

 animals were most brilliantly phosphorescent, and we 

 were afterwards even more struck by this phenomenon 

 in our northern cruise. In some places nearly every 

 thing brought up seemed to emit light, and the mud 

 itself was perfectly full of luminous specks. The 

 alcyonarians, the brittle-stars, and some annelids 

 were the most brilliant. The Pennatulce, the Virgu- 

 larice, and the Gorgonice shone with a lambent white 

 light, so bright that it showed quite distinctly the 

 hour on a watch ; while the light from Ophiacantha 

 spinulosa was of a brilliant green, coruscating from 

 the centre of the disk, now along one arm, now along 





