﻿268 SMITHSONIAN MISCELLANEOUS COLLECTIONS [VOL. 47 



end. As the outer integument of the bulb decayed, the chambers 

 would fill with water, thus causing it to sink gradually to the bottom 

 in its natural position. This mode of segregation would also ex- 

 plain, not only why these bulbs are generally found with the stalk 

 end downward, but also why no crinoid calyxes or crinoidal frag- 

 ments are found (at least very rarely) associated. This hypothesis 

 assumes that the crowns and stalks must in some other area be as 

 plentiful as are the bulbs which make beds replete with them, in 

 Indian Territory extending for ioo miles. In Tennessee, these bulbs 

 are also abundant, and their geographic extent is probably not less 

 than 50 miles. In the Appalachian region Camarocrinus is known 

 plentifully only at one locality. Yet in no place throughout the for- 

 mations in which these bulbs occur are there corresponding beds 

 replete with crowns, stalks, or even accumulations of the separated 

 ossicles. This is the one weak point in the argument that Cama- 

 rocrinus is the float or specialized root of a crinoid. 



To assume that these bodies were anchored in the mud with the 

 stalk directed upward seems to be at variance, not only with their 

 position in the rocks (the great majority are found in a reversed 

 position), but also with their structure. The rounded end of the 

 bulb is full of pores, and what purpose could these have served 

 buried in the mud? In old examples, where all that portion which 

 could have protruded above the mud has the pores covered over by 

 a secondary amorphous coating, this is especially difficult to under- 

 stand. On the other hand, if these bulbs were anchored in the mud 

 during the life of the crinoid, some calyxes or a great mass of 

 crinoidal fragments should have been found with them, yet this is 

 not the case. 



If, as the writer believes, Camarocrinus is the float of a crinoid, 

 it appears to be the only one known either in the fossil or living 

 state. It is a well-known fact, however, that crinoids " present a 

 constant tendency to relinquish the attached mode of life and to lose 

 that typical organ, the stem." 1 In Mesozoic times several genera of 

 crinoids are known to have been devoid of columns and some are 

 thought to have been pelagic. 



Lichcnocrinus represents the nearest approach of a modified crinoid 

 root to Camarocrinus. It, too, is camerate, the radiating striae seen 

 on weathered examples being vertical plates extending upward from 

 the attached base to the inner side of the surface plates. Dr. E. O. 

 Ulrich has also demonstrated their existence for himself by means of 

 thin sections, and has illustrated these features for Mr. S. A. Miller 



1 Bather, op. cit., p. 134. 



