RHIZOGRINUS RAWSON1I. 29 



Apiocrinidte. But in these the basal pieces are always visible on the outside, 

 forming a ring between the enlarged joint and the first radials. In the 

 young Comatulae, when still attached to a stem, the formation of the cup is 

 almost identical with that of Rhizocrinus. To render the proof still more 

 conclusive, I forced a needle through the central hole of the calice of a Rhi- 

 zocrinus lofotensis until it split. The fractures followed the joints between 

 contiguous basals and between the latter and the first radials. 



I copy from Professor Agassiz's note-book some observations he made 

 upon the species described above, while specimens of it were kept alive 

 on deck : — 



" The next haul gave us a Crinoid very mucli like the Rhizocrinus lofotensis, but prob- 

 ably different We had the Crinoid alive for ten or twelve hours. "When contracted the 

 pinnules are pressed against the arms, and the arms themselves shut against one another, 

 so that the whole looks like a brush made up of a few long coarse twines. When the 

 animal opens, the arms at first separate without bending outside, so that the whole looks 

 like an inverted pentapod ; but gradually the tip of the arms bends outward as the arms 

 diverge more and more, and when] fully expanded the crown lias the appearance of a lily 

 of the Lilium Martagon type, in which each petal is curved upon itself, the pinnules of 

 the arms spreading laterally more and more as the crown is more fully open. I have not 

 been able to detect any motion in the stem traceable to contraction, though there is no 

 stiffness in its bearing. When disturbed, the pinnules of the arms first contract, the 

 arms straighten themselves out, and the whole gradually and slowly closes up. It was a 

 very impressive sight for me to watch the movements of this creature, for it told not of 

 its own way only, but at the same time afforded a glimpse into the countless ages of the 

 past, when these Crinoids, so rare and so rarely seen nowadays, formed a prominent 

 feature of the animal kingdom. I could see, without great effort of the imagination, the 

 shoal of Lockport teeming with the many genera of Crinoids, which the geologists of 

 New York have rescued from that prolific Silurian deposit, or recall the formation of my 

 native country, in the hillsides of which, also among fossils indicating shoal water-beds, 

 other Crinoids abound, resembling still more closely those we find in these waters. And 

 now the question may be asked, What is the meaning of the occurrence of these animals 

 in deep waters at the present day, when in former ages similar types inhabited shallow 

 seas ? Of the fact there can be no doubt; for it is not difficult to advance satisfactory 

 evidence of the shoal-like character of the silurian deposits of the State of New York : 

 their horizontal position, combined with the gradual recession of the higher beds in a 

 southerly direction, leaves no doubt upon this point ; and in the case of the Jurassic for- 

 mation alluded to above, their combination with fossils common upon coral reefs and 

 their presence in athols of that period are satisfactory proofs of my assertion. What does 

 it then mean when we find the Pentacrinus and Rhizocrinus of the West Indies in deep 

 waters only 1 It seems to me there is but one explanation for the fact, and that in the 



