OPIIIONEREIS PORRECTA. 



m 



LIST OF SPECIMENS. 



Catalnpie I Oripinal I Numl>er 

 Number. I N umber. | of Siwi;. 



Locality. 



When 

 Collected. 



■Whence obUiincil. 



Nature of 

 i^|leciInen. 



Museum of Comparative Zoology. 

 31 I IKU I 1 I Capo St. Lucas, Cal. | | J. Xantus. | Alcoholic 



1164 



Smithsonian Institution. 

 5 I Cape St. Lucas, Cal. I I J. Xantus. I Alcoholic. 



Ophionereis porrecta Lym.w. (F^igs. u, lo.) 



Ophionercis porrecta Lymak. Proceed. Boston Soc. Nat. Hist., VII. \>. '2G0. 1800. 



Sj)ecial Marks. — Dull reclclish-brown. Arms, in adult specimens, 

 nine times as long as the diameter of the disk. Arm-spines short. 



Description of a Specimen. — Diameter of disk, 12"""- ; from outer 

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

 width of arm without spines, 2.5'°'"'; length of arm, llS"""-; distance 

 from outer side of mouth-shield to inner points of moutli-papilh\?, to 

 that between outer corners of mouth-slits, 2 : 2.2. Mouth-papilU\3 ten, 

 short, stout, the outermost but one broadest. Teeth four or live, stout, 

 squarish, rather long, a little tapering, lowest one shortest. Mouth- 

 shields oval ; length to breadth, 1.6 : 1. Side mouth-shields very small, 

 triangular, sometimes almost obliterated. Under arm- 

 plates squari.sh, broader without than within ; outer side 

 curved, inner side nearly straight, lateral sides re-enter- 

 ingl}' curved; length to breadth (twentieth plate), 1:1.2; 

 (fortieth plate), 1 : 1.4. The first plate is wedge-shaped, 

 with a curved outer side. Upper arm-plates varying in 

 proportionate breadth according to the width of the arm, 

 usually broader than long ; inner side much longer than 

 outer one ; outer and lateral sides sometimes distinguished, 

 and sometimes confounded in a common curve ; length 

 to breadth (sixth plate), .8 : 1.5 ; (thirty-fifth plate), 1 : 1.6. Scales of 

 disk rather stouter than usual in the genus ; about 80 to a square mm. 

 Radial shields 1.2""" long. Scales on edge of di.sk larger than the rest. 

 Papilhv along edges of genital slits stout and prominent. Arm-.<^pines 

 short, rounded, tapering ; lengths to that of under arm-plate (twenty- 



Fig, u. 



Ophionereis piirrecta. 

 (Upper side.) 

 /), arm-spines 



