NORTH PACIFIC OPHIURANS IN NATIONAL MUSEUM CLARK. 211 



68 fathoms, green mud, bottom temperature 45.7, 6 specimens; 

 station 3079, off Oregon, lat. 43 59' 15" N.; long. 124 44' 40" W., 

 55 fathoms, rocky, bottom temperature 46.7, 12 specimens; station 

 3119, off California, lat. 36 56' 30" N.; long. 122 17' 40" W., 54 

 fathoms, rocky, coral, bottom temperature 50.9, 20 specimens; 

 station 3160, off California, lat. 37 48' 35" N. ; long. 123 12' 401' W., 

 39 fathoms, rocky, bottom temperature 51.8, 1 specimen; station 

 3163, off California, lat. 37 56' 40" N.; long. 123 25' 30" W., 69 

 fathoms, fine gray sand, bottom temperature 48.5, 3 specimens; 

 station 3350, off California, lat. 38 58' 10" N.; long. 123 57' 5" W., 

 75 fathoms, fine sand, mud, bottom temperature 48.4, 7 specimens. 

 Bathymetrical range, 39 to 75 fathoms. Temperature range, 51.8 

 to 45.7. Eighty specimens. 



Type. Cat. No. 25647, U.S.N.M., from station 3051. 



This large species, though so variable in many characters, is well 

 defined by its granular disk covering, numerous smooth flattened arm 

 spines, rhombic upper arm plates and two (or even three) long and 

 conspicuous tentacle scales. The specimens before me range in disk 

 diameter from 12 to 23 mm. The most interesting of the variable 

 features is the remarkable diversity shown in the form of the adoral 

 plates; in many cases the oral shield is in contact with the first side 

 arm plate, while the adoral plates are wholly proximal to it; but it 

 is equally common to find the oral shield more or less isolated by 

 the inclosing arms of the adoral plate. Comparison of specimens 

 shows that in the young the adoral plates are proximal to the oral 

 shield, while in large specimens they have pushed down in between 

 the shield and the arm. While this is largely a matter of age it is not 

 wholly so, for great individual diversity is shown; moreover the 

 different mouth angles of a single individual often differ from each 

 other to a notable degree. In view of this condition in this species, I 

 find myself in doubt as to the value of the form of the adoral shields 

 as a generic character in the Ophiacanthidse, and this is one of the 

 chief reasons why I have not followed Verrill's classification. 



OPHIACANTHA ENNEACTIS, new species.a 



Disk 5 mm. in diameter; arms nine, 15 mm. long. Disk closely cov- 

 ered by spines and sharp granules; the spines cover the central area, 

 but are few or wanting at the margins; they are long, straight, slender, 

 sharp and nearly smooth; the granules are most abundant marginally, 

 but are not crowded anywhere; they are sharply conical and end in 

 a glassy tip which may have two or even three points. Radial shields 

 completely concealed. Upper arm plates somewhat pentagonal with 

 the disto-lateral angles rounded; the first one or two are wider than 

 long but the others are as long as wide or longer; all are widely 



a ^Ewta, signifying nine, and d/cr/f , signifying ray, in reference to the number of rays. 



