OPIIIOTIIRIX LINEATA. 



in 



coarser, and of a diflercnt character ; the arm-spines, also, are rather 

 stouter, and the under arm-plates more regular and angular. It is a 

 larger species than O. violacea or 0. anrjulata, and differs from them in 

 coarser spines on the disk, and jiroportionately longer arm-spines. 



LIST OF S r E C I M E N S , 



Ophiothrix lineata Lyman. 



Ophiothrix lineata Lyman. Proceed. Boston Soc. Nat. Hist., VII. p. 201. 18G0. 



Special Marks. — Brownish red, with a black line along the uj)per 

 side of the arm. Arm-spines usually six, stout. 



Descrijjilon of a Specimen. — Diameter of disk, 10"""-; from outer 

 edge of mouth-shield to outer corner of opposite mouth-slit, 4.5"°'' ; 

 width of arm without spines, 2'"'°- ; length of arm, GS"""-. Tooth-papillas 

 fine, numerous, cylindrical, resembling short, blunt spines. Mouth- 

 shields broad oval, with a slight peak toward mouth ; length to 

 breadth, 1 : 1.5. Disk, above, w4th large radial shields, which are 

 smooth, or very nearly so, shaped like an elongated triangle, the acute 

 angle being turned inward, separated by a distinct stripe ; length to 

 breadth, 2.8 : 1.7 ; the narrow brachial and broad interbrachial spaces 

 form ten stripes, radiating from the centre ; both centre and stripes are 

 covered with elongated scales (only to be seen on dried specimens), 

 and these again bear many little grains, each with a crown of thorns ; 

 below, interbrachial spaces quite naked. Upper arm-plates broad hex- 

 agonal, with corners a little rounded, the two side angles more acute 

 than the others ; length to breadth, .7 : 1.5. Under arm-plates nearly 

 oval, but with some indications of angles ; length to breadth, .8 : 1.2. 

 Arm-spines rather stout, flattened, cut off square at the end, varying in 

 length ; about six in number on joints close to disk ; two upper ones 



