﻿OPIIIOTIIRIX LINEATA. 



171 



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

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

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

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



LIST OF specimen: 



\\Tience obtainei]. 



Museum of Comparative Zoology. 



140 I 1049 I 1 I San Diego, Cal. I I Mr. Cassidy. 



338 . . 1 Guayamas, Gulf of Cal- 



I I I ifornia. | | Capt. Stone. 



Siinlhsonian Iiistitulion. 

 1049 I • • I 2 I San Diego, Cal. I I Mr. Cassidy. 



Ophiothrix lineata Ltman. 



OpMothrix lineata Lymax. Proceed. Boston Soc. Nat. Hist., VII. p. 201. 18G0. 



Special Marks. — Brownish red, with a black Une along the upper 

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



Descr'qotion of a Sjjecimen. — 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, 63°"°-. Tooth-pap illiB 

 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, with 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 



