256 HAWAIIAN AND OTHER PACIFIC ECHINI. 



half; the width of the base is .30 mm. The blade is tubular, ending in the 

 usual sharp tooth, which may be as much as .20 mm. long. The ophicephalous 

 are conspicuous because of their long, stout stalks and heavy heads; the valves 

 are .30-.40 mm. long, besides the loop, which adds .03-. 10 mm. more, and are 

 not constricted above the base; their general form is similar to those of Echinus 

 lylodes (PL 93, fig. 12}. The tridentate pedicellariae vary greatly in size but are 

 otherwise all alike; the valves, which range from .40 to 1.00 mm. in length, are 

 rather narrow and are strongly compressed at the base of the blade. The 

 triphyllous are not peculiar; the valves measure about .20 mm. in length by .15 

 in breadth of blade. The sphceridia are not peculiar. The calcareous spicules 

 of the tube-feet although arcuate, are scarcely bihamate. 



The ground color of the test is dull white, at least actinally, becoming grayish 

 or greenish abactinally, where it is blotched or marbled with dull olive-green or 

 purplish brown. The spines are dull greenish, or yellowish becoming lighter 

 at the tip; they are often dirty cream-color. Although very variable in detail, 

 the general impression of this sea-urchin as seen from above is dull olive-green, 

 mottled with cream-color, or cream-color mottled with dull shades. 



This interesting species seems to be abundant off southern and Lower Cali- 

 fornia in water of moderate depth. Apparently it is not littoral for none of the 

 collectors who have gathered the shore forms there seems to have found a speci- 

 men. It cannot be confused with any other echinoid of that region, nor does it 

 approach very closely to any known member of the Echinidse. But the variable 

 character of the abactinal system, the tendency of the buccal membrane to 

 become less heavily plated in adults, and the appearance of the pedicellarise 

 all point to the "intermediate" position it occupies between euerces and semi- 

 tuberculatus. 



It was taken by the "Albatross" at the following places: 



Station 2838. Off Cedros Island, Lower California; 28 12' N., 115 9' W. 

 Bott. temp.? 44 fathoms. Gn. m. 



Station 2899. Off Santa Barbara, California; 34 N., 120 23' W. Bott. 

 temp.? 44 fathoms. Gy. s., brk. sh. 



Station 2906. Off Santa Barbara, California; 34 23' 30" N., 120 19' 30" W. 

 Bott. temp. 55.5. 9G fathoms. S., m. 



Station 2907. Off Santa Barbara, California; 34 24' 30" N., 120 20' W. 

 Bott. temp.? 44 fathoms. Fne. gy. s. 



Station 2913. Off San Diego, California; 32 25' 30" N., 119 3' 30" W. 

 Bott. temp. 59. 26 fathoms. Brk. sh. 



