OPHIUROIDEA OF THE BAHAMA EXPEDITION. 13 



Our specimens have the radial shields, broad, ovate and 

 not widely separated, only three rows of small plates inter- 

 vening, of which the lateral are minute; their inner ends are 

 not so divergent as in the type. According to Mr. Lyman 

 all the side arm-plates meet above and below "from the very 

 innermost joint." In ours they do not meet above on the 

 two basal joints and barely touch on the third. The upper 

 arm-plates at the base of the arms are quite unlike Mr. Ly- 

 man's figure and description. The first (preceded by a 

 smaller transverse, supplementary radial) is transversely el- 

 liptical, large, much wider than long; the next is six-sided, 

 large, longer than broad, truncated proximally, angulated 

 distally and laterally; the third is also rather large, longer 

 than broad, rhombic, with the inner half longer and more 

 acute than the outer; beyond the third the plates are of similar 

 shape, but rapidly decrease in size, as described by Lyman. 

 The arm-spines are three, instead of two, and are not all 

 "nearly equal." They are small, short, blunt, the lowest are 

 longest; distally the lowest one becomes more decidedly 

 longer and stouter than the others. The under arm-plates 

 are not all "three-sided and very small," for the two basals 

 are rather large for the genus, somewhat five-sided, or 

 trapezoidal, with the corners rounded and the outer end eith- 

 er obtusely angulated or convex. 



The oral shields are longer than figured by Mr. Lyman, 

 much longer than wide, the distal half with nearlv parallel or 

 slightly curved sides, the outer end convex, the proximal sides 

 convergent to an acute angle, so that the form is very acute- 

 ovate. The adoral shields are long, triangular, with their 

 very acute proximal ends touching. The mouth-papillae are 

 mostly flattened and thick; the next to the outer is broadest, 

 the others decreasing in size successively. Diameter of disk 

 of largest specimen figured, 12 mm., length of arms about 

 42 mm. Diameter of disk of the smaller one figured, 10 mm. 



Off Havana, no to 260 fath., four examples. Taken by 

 the Blake Exp. in 92 to 500 fath. 



