34 Piih. Paget Sound Biol. Sta. Vol. 2, No. 33 



Genus Ophiura 

 1. Ophiura brevispina Say. 



Disk small, pentagonal, not thicker than rays ; rays 5, long, slender, 

 from corners of disk-pentagon, limited in movement. Spines on disk none; 

 plates on upper and lower side of disk overlapping like fish-scales ; scales 

 small except a large one on each side of the base of each ray ; mouth-shields 

 very large, interradial. Ray plates well developed ; lateral plates bearing 

 4 or 5 graded spines, the longest above, all parallel to the axis of the rays. 

 Many mouth papillae and spines present. Color various. — Numerous, in 

 deep water. 



Genus Ophiopholis 

 1. Ophiopholis aculeata (Linnaeus) Gray. 



Rays 5, long, slender, not covered with skin, movement limited. Disk 

 small, covered with small conical spines and a series of 3 to 5 rounded 

 plates on the upper side from the base of each ray almost to the center, 

 o-lobed ; disk-lobes alternating with the rays, showing conspicuously on 

 the lower side. Plates of rays well developed ; the lateral plates each 

 bearing 5 spines on each side; the spines varying in length, the middle 

 cue the longest. Usually red. — Rather numerous, in deep water, often on 

 holdfasts of kelp (Nereocystis). 



Genus Amphiodia 

 1. Amphiodia periercta Clark. 



Disk pentagonal in form, 20 mm. in diameter; rays slender, 15 cm. 

 or more in length. Surface of disk covered with overlapping scales; spines 

 none. Oral papillae 3 on each side, thick, rounded and subequal. Radial 

 shields small, somewhat pentagonal, with an inner angular and an outer 

 curved margin. Side arm-plates small, with 3 sharp arm-spines of which 

 the middle one is slightly the longest. Color in dried specimens pale 

 yellowish brown. 



Found buried in about 15 inches of sand at Olga, Washington, by 

 Dean Engberg of the University of Nebraska. 



Genus Amphioplus 

 1. Amphioplus abditus Verrill. 



Small, delicate; rays slender, long, 12 to 18 times the diameter of 

 the disk. Disk rather thick, not deeply lobed, lobes alternating with the 

 rays ; spines none ; surface covered with overlapping plates, all small except 

 2 at the base of each ray on the upper side; these pairs large, longer than 

 broad, not closely joined. Rays originating from shallow grooves on the 

 under side of the disk; movement in a vertical plane and toward mouth. 

 Dorsal plates of rays not surrounded by smaller plates ; lateral plates each 



