CAPTAIN OWEN ON THE SUErAOE-FAUNA OE MID-OCEAN, 203 



course to latitude 33° north, and longitude 44° west, the equator 

 being crossed in longitude 22° west. A register has been kept 

 of the different species of animal life met with in each portion of 

 these long tracts of ocean-surface, and rarely has the sea been 

 found free from some species of Polycystina. 



Many of these forms have been hitherto claimed by the geolo- 

 gist ; but I have found them still enjoying life, according to their 

 small powers, in this their true home, the siliceous shells filled 

 with coloured sarcode, and sometimes this sarcode in a state of 

 distention somewhat similar to that found projecting from the 

 Foraminifera, but not in such slender threads. 



I will now make a few observations on the appearance of these 

 little gems of ocean. Having seen the Polycystina fresh from 

 their native element in all their living splendour, I can assert 

 that there are no objects in nature- more brilliant in their 

 colouring or more exquisitely delicate in their forms and struc- 

 ture. Unfortunately these tints can rarely be preserved. I have, 

 however, coloured a few drawings to illustrate their appearance 

 when fresh from the sea. Some are of but one colour — crimson, 

 yellow, or blue ; sometimes two of these colours will be found in 

 the same individual, but always separate, and rarely if ever mixed 

 to form green or purple. In a globular species, whose shell is 

 made up of the most delicate fretwork, the brilliant coloiirs of the 

 contained blue and yellow sarcode shine through the little per- 

 forations very prettily. In two other specimens of the triangular 

 and square forms, the respective tints of yellow and crimson are 

 vivid and delicately shaded. In one the pink lines are concentric ; 

 while another is of a stellate form, the points and uncoloured 

 parts being bright clear crystal, a beautiful crimson ring sur- 

 rounding the centre portion. 



I have dwelt upon the colours in order to give some idea of 

 their natural appearance in the living state. The beautiful forms 

 and delicately fine structure could be nearly as well seen in the 

 fossil specimens. 



The Polycystina appear to avoid the light, as they are rarely to 

 be found on the surface of the sea in the daytime ; it is after 

 sunset, and during the first part of the night especially, that they 

 make their appearance. I cannot say whether they make the 

 bottom of the ocean their home during the day. The weight of 

 their siliceous coverings would no doubt allow them to sink ra- 

 pidly ; and if they do so but to the distance of a few fathoms, it 

 proves that they must have some means of extracting air from the 



