32 NATURAL .HISTORY BULLETIN. 



versely elliptical, short, with the outer edge evenly convex; 

 they are somewhat thickened and broadly joined. 



Oral shields small, transversely broad-elliptical, convex and 

 slightly angulated distally, obtusely angulated on the inner 

 end. Madreporic shield decidedly larger and more rounded. 

 The large genital slits nearly reach the oral shields; their in- 

 ner ends are separated only by a narrow isthmus, covered by 

 two narrow genital scales, which join the outer end of the 

 oral shield. Adoral shields small, trilobed. the acute inner 

 ends separate, or sometimes barely touching. 



Color of one example deep green above, with small white 

 spots on the outer end of the radial shields, on the central 

 part of the disk, and on the upper arm-plates Under side 

 whitish, the arms becoming greenish distally. The four low- 

 er arm-spines are white; the two or three upper ones are 

 green. Another example, from station 69, is greenish black 

 above, with fewer white markings, but whitish below. 



Diameter of disk, 7-5 mm-"? length of longest arm, broken at 

 tip, 44 mm. 



Stations 69 and 74, Bahama Banks, in shallow water. 



Mr. Lyman sent to me, several years ago, several speci- 

 mens essentially like those described above, but of still larger 

 size, as "O. miilleri, var. quinqueradia" This variety name, 

 first given in 1878, appears in the Voyage of the Challenger 

 (pp. 113, 115), but with no definite description nor figure.* 

 I am not aware that it has been described elsewhere under 

 that name. In his earlier work -j- Mr. Lyman described a 



*This name appears without description in Bull. Mus. Comp. Zool., 

 vol. V, p. 224, 1878. The specimens were from Key West and vi- 

 cinity in shallow water (shore to 37 fath). 



In the Voy. Challenger, p. 113, in the analytical table, it is men- 

 tioned as the adult of O. mu/leri, and is said to have: "Upper arm- 

 plates transverse oval and not thickened; three or even four mouth- 

 papillae on a side." In the specimens sent to me the upper arm- 

 plates are thickened and there are three small mouth-papillae. 



•flllust. Catal. Mus. Comp. Zool., I, p. 109, 1865. 



