NO. 2 ZIESENHENNE: NEWOPHIURANS 27 



Types. — Holotype, AHF no. 13; 15 paratypes. 



Type locality. — Holotype and 5 paratypes from Station 529-36, 165 

 fms., off San Francisquito Bay, Lower California, March 1, 1936, Ten 

 paratypes as follows: 2 from Station 526-36, 3-5 fms., off Mangles 

 Anchorage, Lower California, February 28, 1936; 5 from Station 534- 

 36, 125 fms., off San Francisquito Bay, Lower California, March 2, 

 1936; and 3 from Station 750-37, 60 fms.. Outer Gorda Bank, Lower 

 California, April 4, 1937. 



Remarks. — In the smaller specimens the dorsal arm plates are not 

 divided. O. calif ornica can be distinguished from O. hispida (Le Conte) 

 by the oral shields, which are about as long as broad ; the outermost oral 

 papilla, which is longer than broad ; radial shields half in contact ; upper 

 arm plates triangular, divided into several pieces in the adults; and the 

 arm length, which is 5 times the disk diameter, while the arm length of 

 O. hispida is 10 times the disk diameter. From the other members of the 

 genus, O. calif ornica can be readily distinguished by the unique upper arm 

 plates and the oral shields. It has been named calif ornica, as the range of 

 this species seems to be confined to the Gulf of California. 



Genus AMPHIOPLUS Verrill 



Amphioplus philohelminthius, new species 



Plate 5, Figs. 7-9 



Description. — Disk diameter, 4 mm.; arms, 51 mm. long. Disk small, 

 pentagonal, with a central and 5 radial primary disk plates ; disk covered 

 with small uniform scales, those bordering the radial shields larger. 

 Radial shields large, the length more than half the disk radius, about 3 

 times as long as broad, slightly separated proximally but in contact dis- 

 tally ; somewhat swollen and raised above the remainder of the disk. 



First upper arm plate wider than long. Succeeding plates oval, slightly 

 wider than long, becoming more so distally, widest proximally, with a 

 convex margin, distal margin sharply rounded. At the arm extremities the 

 plates become longer than wide and rounded pentagonal or triangular. 

 The plates are separated by the side arm plates throughout the arm 

 length. 



Side arm plates 3 times as broad as long, separated from each other 

 by a naked membrane. Spine ridge prominent, bearing 4 flattened, lanceo- 

 late, blunt-tipped spines on the 10 basal arm segments, 3 subequal spines 

 on the remainder of the arm, median spines shorter than upper and 

 lowermost. 



