454 THE DEPTHS OF THE SEA. [CHAP. ix. 



that the syzygies are not repeated, so that there is 

 only one of these peculiar junctions in each arm. 

 The arm-grooves are bordered by circular fenes- 

 trated plates, as in Rhizocrinus. 



Certain marked resemblances in the structure of 

 the stem, in the structure of the base of the cup, 

 and in the form and arrangement of the ultimate 

 parts of the arms, evidently associate Bathycrinus 

 with Rhizocrinus, but the differences are very wide. 

 Five free keeled and sculptured first radials replace 

 the uniform smooth ring formed by these plates 

 in Rhizocrinus. The radial axillaries give off each 

 two arms, thus recurring to the more usual arrange- 

 ment in the order, and the alternate syzygies on 

 the arms, which form so remarkable a character in 

 Rhizocrimis, are absent. 



Only one nearly complete specimen and a de- 

 tached stem of this very remarkable species were 

 met with, and they were both brought up from the 

 very greatest depth which has as yet been reached 

 with the dredge, 2,435 fathoms, at the mouth of 

 the Bay of Biscay, 200 miles south of Cape Clear. 



It would seem, in our present state of knowledge, 

 that the stalked crinoids are members of the deep- 

 sea fauna. A second specimen of another very 

 remarkable form, Holopus rangi, D'OKBIGNY, has 

 lately been procured from deep water off Barbadoes, 

 and that species, with those already noted, makes 

 up the tale of living forms belonging to the order 

 which are known at the present time. It is unwise 

 to prophesy; but when we consider that the first 

 few scrapes of the dredge at great depths have 

 added two remarkable new species to the living 





