MONOGRAPH OF THE EXISTING CRINOIDS. 



89 



Internodes. In the pentacrinites, the sections of the stem between the nodals (see 



fig. 127, p. 197). 



Interpalmar. Same as Interambulacral. 

 Interpalmar areas. See Interambulacral areas. 



FIG. 62. 



FIG. 63. 



Fios. 62-64. 62, DIAGRAM SHOWING THE ANALYSIS OF A CHIASMA AND THE COMPARATIVE RELATIONSHIP BETWEEN A CHIA.SMA 

 AND THE CENTRAL NERVOUS STRUCTURES (FIG. 64) (DRAWING BY THE AUTHOR). 63, DIAGRAM SHOWING THE COURSE OF THE 

 NERVES IN METACRINUS ROTUNDUS (DRAWING BY THE AUTHOR). 64, DIAGRAM OF ONE OF THE FIVE NERVE UNITS OF THE 

 CRINOIDAL DORSAL NERVOUS SYSTEM, SHOWING ITS INTERRELATIONSHIPS WITH THE ADJACENT SIMILAR NEBVE UNITS (DRAWING 

 BY THE AUTHOR). 



Inter pinnulars. Small porisomic plates sometimes de velopcd between the bases of 

 adjacent proximal pinnules when these are incorporated in the body wall. 



Interpolated arm division. Arm division in which the division scries are redupli- 

 cations of the first two or first four ossicles of the free undivided arm, as in 

 most of the recent comatulids (see figs. 61a-c, p. 87). 



79146 Bull. 8215 7 





