REPORT ON THE OPHIUROIDEA. 



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Ophiothrix magnified stands near, having a long genital plate reaching nearly to the 

 mouth shield, and a hollow lozenge on top the first free arm bone ; the genital scale too is 

 extremely large and thick, and has a slightly lobed edge. The radial shields, however, 

 are smaller than usual, with crusty, rounded, not elongated, scales in the interbrachial 

 spaces. 



Ophiothrix suensonii, which leads a distinct group of Ophiothrices, presents some 

 variations in the skeleton. The radial shields are of great size, massive, and with smooth 

 edges, and the pairs are scarcely separated. The first free arm bone has a slight elon- 

 gation on its upper surface. The genital plate is flat and much thinner than in species 

 already treated. The upward forward apophysis of the arm bones is even longer than 

 usual, and of a somewhat different form. 



See Plate XL 1 1, figs. 5-8. 



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Table op Species op Ophiothrix. 



Large (disk 16 mm.). Radial shields somewhat sunk in ) 



swollen disk, which bears various short stout stumps, ■ Ophiothrix fragilis 

 mingled sometimes with a few slender long spines, . . ) 



Small (disk 11 mm.). Radial shields somewhat sunk in 

 puffed disk, which is evenly beset with trifid stumps, 

 mingled with a few cylindrical spines, 



Similar to Ophiothrix echinata, but lowest arm spine as far 1 

 inward as seventh joint is a double or triple hook, . j 



Large and similar to Ophiothrix fragtilis, but with short thin ) 

 arm spines, high arched arms, and minute spines on upper 

 arm plates, . . . . . . . ) 



Similar to Ophiothrix fragilis (same 1). Disk beset with ) 

 ttiorny grains, conical stumps, and very stout, columnar > 

 spines. . . . . . . .1 



Disk above closely set with grassy fluted spines, without ) 

 stumps. Radial shields naked, except sometimes a few 

 minute spines, . . . . . . | 



Similar to Ophiothrix echinata (same ?), but larger and disk ) 

 beset with stouter stumps, and spines having crowns of 

 three to seven thorns, . . . . . | 



Similar to Ophinlhrix pentaphyllum (same 1 !), but only seven ^ 

 arm spines, and with a red spot on each upper arm plate, . j 



Ophiothrix echinata. 

 Ophiothrix rosi oca rulans. 



Oph iotli /■/.(• Hit hen i. 



Ojihin/hri.i /iriifaphi/Uiiw. 



Ophiothrix dlopecurus. 



Ophiothrix lusitanica. 

 Ophiothrix maculata. 



Arms seven to ten times diameter of disk. A few long disk spines which are 

 jointed on little mamelons. ...... 



{' Oph 



hiothrix quinquemaculata. 



Second and third arm spines largest and slightly club-ended. Disk set with ) 



short thorny cylinders. Radial shields naked. Under arm plates trans- > Ophiothrix fumaria. 



verse oblong with rounded corners, . . . . .1 



