MONOGRAPH OF TUB EXISTING CKINOIDS. 



75 



Chiasma. The figure formed by the division of the dorsal norvo trunks within the 

 axillarios (fig. 62, p. 89). 



Immediately upon entering the axillary the nerve cord divides into two parts 

 which run each to the center of one of the two distal articular faces. A trans- 

 verse connective unites these two branches just before they emerge from the 

 distal faces of the axillary. Shortly after the branching of the primary nerve 

 cord a small branch is given off from the inner side of each derivative ; these 

 two branches run obliquely outward, distally crossing each other and immedi- 

 ately merging with the transverse connective. 



Fio. 36. 



FIG. 37 



Fio. 38. 



FlG. 39. 



FIG. 40. 



FlG3. 36-10. 36, A TYPICAL CHYPTOSYNARTHRY FROM A SPECIMEN OF TOMATULA PECTINATA FROM SINGAPORE. 37, TnE PSEUDO- 

 SYZYGY BETWEEN THE OSSICLES OF THE IBR SERIES IN A SPECIMEN OF COMASTEH FRCTICOSCS FROM THE PHILIPPINE ISLANDS. 

 38, THE TWO ARTICULATING SURFACES OF THE PERFECTED PSEUDOSYZYGY BETWEEN THE FIRST TWO BRACHIALS IN THE TYPE 

 SPECIMEN OF COMATULA PURPUREA FROM AUSTRALIA. 39, THE PERFECTED PSEUDOSYZYGY BETWEEN THE OSSICLES OF THE 

 IBR SERIES IN A SPECIMEN OF CoMATULA MICRASTER FROM THE ANDAMAN ISLANDS. 40, TllE PERFECTED PSECDOSYZYGY 

 BETWEEN THE OSSICLES OF THE OUTER DIVISION SERIES IN A SPECIMEN OF CoMASTER FRUTICOSUS FROM THE PHILIPPINE 

 ISLANDS. 



The chiasma within the axillaries is a reduplication of conditions accom- 

 panying the division of the primary nerve cords within the calyx (see figs. 62-64, 

 p. 89, and pp. 350-354). 



Cirral. A single cirrus segment (see figs. 1, p. 60, and 4, p. 63). 



Cirrhdl. Same as Cirral. 



Cirrhi. See Cirri. 



Cirri. In the comatulids and pentacrinites ; jointed appendages arising in the 

 former from the centrodorsal, and in the latter from specialized columnals 

 (nodals) which occur at regular intervals throughout the stem (see figs. 1, p. 

 60, 4, p. 63, and 127, p. 197 and pp. 258-312); (see Badicular cirri). 



