A. H. CLARK: THE CRINOIDS OF THE INDTAN OCEAN. 311 



sition; like the arm bases they are more or less flattened against each other; the 

 brachials are of the typical short-discoidal type, and have strongly produced 

 distal edges : the distal edges of the ossicles of the division sei-ies are also slightly 

 produced, and are finely spinous. 



The details of the arm division are as follows : — 



Ray 1 : Two IIBr 2 series : that to the left (viewed dorsally) l)ears out- 

 wardly (on the left) a III Br 2 series and inwardly (to the right) an undivided arm ; 

 both of the undivided arms arising from the IIIBr series have the first syzygy 

 between the second and third brachials, but the (internal) undivided arm arising 

 from the IIBr series has the first syzygy between the third and fourth brachials ; 

 the I IBr series to the right bears inwardly (toward the left) an undivided arm in 

 whicii the first syzygy is between the third and fourth brachials, and outwardly 

 (toward the right) a IIIBr 5 (44-5) series, the two derivatives from which have the 

 first syzygy between the second and third brachials. The total number of arms 

 on this ray is six, arranged in 2, 1, 1, 2 order. 



Ray 2 : Two IIBr 2 series ; that to the left bears two undivided arms in 

 which the first syzygy is between the third and fourth brachials ; that to the 

 right bears inwardly (to the left) a IIIBr 4 (3-|-4) series, both derivatives from 

 which have the first syzygy between the second and third brachials, and outwardly 

 (to the right) an undivided arm in which the first syzygy is between the third and 

 fourth brachials. The total number of arras on this ray is five, arranged in 

 1, 1, 2, 1 order. 



Ray 3 : Two IIBr 2 series ; that to the left bears externally (to the left) an 

 undivided arm in which the first syzygy is between the second and third brachials, 

 and internal^ (to the right) two IIIBr series, all four derivatives from which 

 have the first syzygy between the second and third brachials ; the IIBr series to 

 the right bears two undivided arms in which the first syzygy is between the 

 second and third brachials. The total number of arms on this ray is seven, 

 arranged in 1, 4, 1, 1 order. 



Ray 4: IIBr series to right 4 (3-|- 4); IIBr series to left 2 ; the IIBr 4 (3+4) 

 series bears two IIIBr 3 (2+3) series ; in the four derivatives from these the first 

 syzygy is between the second and third brachials in all cases except on the inner- 

 most (furthest to right) arm where it is between the fifteenth and sixteenth bra- 

 chials ; the IIBr 2 series bears two IIIBr 2 series ; of these the inner (to the left) 

 bears two IVBr 3 (2+3) series; the outer (to the right) bears inwardljj^ (to the 

 left) a IVBr 3 (2 + 3) series and outwardly an undivided arm; in all the deriva- 

 tives from this IIBr 2 series the first syzygy is between the second and third bra- 

 chials The total number of arms on this ray is eleven, arranged in 2, 2, 4, 3 

 order. 



Ray 5 : Two IIBr 2 series ; that to the left bears externally (to the left) an 

 undivided arm, and internally (to the right) a ,IIIBr 3 (2+3) series; that to the 

 right bears internal^ (to the left) an undivided arm and externally (to the right) a 

 IIIBr 2 series which bears internally (to the left) a IVBr 4 (3 + 4) series and 



