OPHIUROIDEA OF THE BAHAMA EXPEDITION. 2 n 

 Amphipholis tenera (Ltk.) Ljung. 



Amphiura tenera Liitken, Addit. ad. Hist. Ophiur. Pt. II, p. 124, pi. 

 Ill, figs. Sa, 5b, 1857. Lyman, 111. Cat. Mus. Comp. Zool., I, p. 123. 



Amphipholis tenera Ejung., Ophiur. Viv., Kong. Akad., 1866, p. 312; 

 op. cit., 1871, pp. 634, 645. 



Disk rounded, thin, flat, covered with numerous small 

 rounded scales, regularly arranged. Those along the mar- 

 gins with their edges a little turned up, so as to form a slight 

 border. Radial shields rather crescent-shaped, in close con- 

 tact. Arm-spines three, slender, tapered, nearly equal in 

 length, but the middle one is distinctly swollen toward the 

 base; they are about as long as the length of an under arm- 

 plate. Tentacle-scales two, small, oblong, blunt, about equal 

 in size. The outer mouth papilla is flat, much the broadest, 

 occupying about half the length of the mouth-slit; the middle 

 one is small, subconical; inner one a little larger. 



Oral shields top-shaped, about as long as broad, the outer 

 end strongly rounded, the inner sides nearly straight and con- 

 vergent to an acute angle. Lateral oral shields relatively 

 large, oblong, a little wider distally, the inner ends largely in 

 contact. 



Under arm-plates oblong shield-shaped, decidedly longer 

 than wide, outer end convex, sides nearly straight, inner end 

 angulated; they are strongly separated by the side-plates. 



Upper arm-plates relatively large, rather broader than 

 long, subtriangular, the outer end broadly rounded, the inner 

 end obtusely angulated; they are well separated by the side 

 plates. 



Diameter of the disk of the specimen described, which is 

 not full grown, 2 mm: length of arms (broken at tips), 

 9 mm. 



Off Havana, ioo to 200 fathoms. Charleston, S. C. to 

 West Indies, in shallow water. 



Mr. Lyman, in the Voyage of the Challenger, united this 

 species and several other forms that have been described as 



