104 THE DEPTHS OF THE SEA. [CHAP. HI. 



aperture does not penetrate the plate, but perforates 

 a membrane which fills up a diamond-shaped space, 

 one-half of which is cut out of the outer edge of the 

 ovarial plate in the form of a large triangular notch, 

 while the other half is formed by a separation into a 

 like notch of the two upper interradial plates, in the 

 middle line of the interradial space. The charac- 

 teristic paddle-shaped spines are ranged in several 

 rows round the mouth. The large spines round the 

 equator of the corona are diverse in form, some of 

 them cylindrical, only slightly tapering towards the 

 tip, and others bulging out and thick near the neck 

 and coming somewhat rapidly to a sharp point. The 

 colouring of the animal is very remarkable. The 

 short spines covering the test are of a rich purple, 

 and a purple of even a deeper and richer hue dyes 

 about one-third of the length of the spine, from the 

 head of the spine outwards, ending abruptly in a 

 sharply defined line. The spine beyond this purple 

 portion is of a beautiful pale rose colour. Two 

 mature examples of this fine species were found, and 

 two young ones, one nearly half-grown and the other 

 much smaller. 



We now moved slowly to the northward towards 

 the Eseroe Bank, and soundings were taken to fix as 

 closely as possible the point of passage from the warm 

 water into the cold : a temperature sounding taken in 

 lat. 59 37', long. 7 40', gave a depth slightly less 

 than that of the ( Holtenia ground/ 475 fathoms, 

 with a slightly higher bottom temperature, 7'4 C. ; and 

 at Station 50, lat. 59 54', long. 7 52', with a depth of 

 335 fathoms, the minimum temperature had risen to 

 7'9 C. A sounding at Station 51, lat. 60 6', long. 



