16 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 



Oral shields elongated, almost twice as long as broad. An acute angle 

 within and a lobe without, outer side margins slightly concave. Adoral 

 plates triangular, broader than long, widest without. All margins slightly 

 concave; not quite meeting within. Jaws very small, triangular, broader 

 than long. Three oral papillae on a side, outermost triangular, about as 

 long as wide; median bluntly rounded, slightly longer than wide; inner 

 rectangular, blocklike, longer than wide, widely separated. Four teeth, 

 ventralmost short and triangular, next 3 broad and rectangular, increas- 

 ing in length to the uppermost, which is the longest. 



Interbrachial spaces below covered with large overlapping disk scales, 

 as large as those on the upper surface. Genital slits inconspicuous, con- 

 cealed by the arm spines. First under arm plate small, rectangular, wider 

 than long, margins straight. Succeeding plates pentagonal, about as wide 

 as long, angle within, proximal lateral and lateral margins almost 

 straight, distal margins concave. Plates barely in contact or separated by 

 the side arm plates. Two small oval tentacle scales placed at right angles 

 to each other, innermost slightly the longer. 



Color. — Dried from alcohol, the holotype was a dark olive buff on 

 both upper and under surfaces without any special markings. 



Types. — Holotype, AHF no. 21 ; 4 paratypes. 



Type locality. — Station 177-34, 5-20 fms., Sulivan Bay, James 

 Island, Galapagos, January 23, 1934. Four paratypes from Station 337- 

 35, 2-5 fms., Sulivan Bay, James Island, Galapagos, December 12, 1934. 



Remarks. — This species seems to be confined to the Galapagos 

 Islands. It can readily be distinguished from all known species of the 

 genus by the 10 large marginal papillae, longer than the arm spines. The 

 papillae are well spaced, 2 in each interradius. In the 5 specimens exam- 

 ined, not more than 2 papillae were found in any interradius. In dredging, 

 several papillae were crushed and broken, but prominent scars remained 

 to mark their location. The name disacanthus has reference to the 2 mar- 

 ginal disk papillae in each interradius. 



Ophiophragmus lonchophorus, new species 

 Plate 4, Figs. 4-6 



Description. — Disk diameter, 3 mm. ; arms, 23 mm. long. Disk circu- 

 lar and swollen, covered with large, polygonal, overlapping disk scales. 

 There are several conspicuous disk scales but no central disk plate or 

 rosette arrangement. In the interbrachial areas are 5 rows of disk scales ; 



