-ill University of California Publications in Zoology. [Vol.6 



(c 6), 30-40 fathoms, 1874. No. 2 (Henry Hemphill), San Diego. Smith- 

 sonian: 12644, W. H. Dall (c 7), Catalina Harbor, 40 fathoms. 4290, 

 Catalina. 



Genus Ophiocten Ltk. 1854. 



Disc thick and circular, partly covered by plates and radial 

 shields between which are sometimes fine, close-set grains or small 

 scales. Genital opening bordered by a row of papillae that often 

 extends upward along the edge of the disc, over the arm base. 

 Side arm plates come together below but not above. The broad 

 mouth tentacle is enclosed between the first ventral arm plate 

 and the outer edge of the side arm plate. Teeth. Mouth pa- 

 pillae. No tooth papillae. Two genital openings beginning at 

 the sides of the mouth shield. 



Ophiocten pacificum L. & II. 



Figs. 14, 15. 

 Mem. Mus. C'omp. Zool., XXIII, No. 2, 1S99. 



Diameter of disc 12 mm. Length of arm a little more than 

 three times diameter of disc. Disc covered with separated plates 

 and radial shields and the areas between them covered with im- 

 bricated scales. Eadial shields narrowed within. Five to sis 

 pairs of mouth papillae in each jaw. the inner one spinous. Teeth. 

 No tooth papillae. Mouth shield pentagonal, inner angle sharp, 

 remaining ones rounded. Side mouth shields meeting within, 

 narrowed without. Genital openings begin at sides of mouth 

 shield, bordered with papillae that are continued up over arm. 

 First pair of tentacle pores between basal arm plate and side 

 month shields, each with two broad scales. Second pair of 

 tentacle pores each with a bilobed scale. The remainder, each 

 with one flat and one minute spinous tentacle scale. Ventral 

 arm plates small and well separated. The first one trapezoidal, 

 narrowed proximally. Side arm plates meeting below. Dorsal 

 arm plates broader than Long, narrowed proximally and convex 

 distally, the proximal plates bearing minute spinous papillae on 

 their distal margin. Three slender, slightly curved arm spines, 

 the dorsal spine longer than two arm joints, the ventral spine a 

 little longer than one arm joint. 



From Galapagos Ids. anil Gulf of Panama to San Diego; down to 1573 

 fathoms. 



