226 



SIDONOPS OXYASTRA. 



Northeastern Pacific. West coast of North America; near Santa Barbara 

 Islands. "Albatross" Station 4417. 



Sidonops angulata var. orthotriaena LENDSNFiSLD. 

 Ante, p. 24. 



Stout choanosor?ial amphioxes up to 70 /^ thick. Slender dermal amphi- 

 oxes, not numerous, up to 17 /< thick. Anaclades, triaene, rhabdome up to 

 18 fi thick, chides up to 80 /< long. Strongylosphaerasters with nearly cylindrical 

 rays. Sterrasters up to 111 fi long; besides the ellipsoidal also rhomboidal ones 

 occur. 



Northeastern Pacific. West coast of North America; 34° N. "Albatross" 

 Station 2945. 



Sidonops oxyastra Lendenfei.d. 

 Ante, p. 40. 



Lobose. In spirit : brownish white to purplish brown. 



Large choanoso7nal amphioxes: 1.1-1.55 by 10-32 //. Large amphistrongyles : 

 0.8-1 mm. by 18-23 pt. Large styles: rare, 850 by 38 pt. Minute dermal styles: 

 130-230 by 3-5.5 //. Plagiotriaenes: rhabdome 1-1.65 by 24-40 p.; clades equal, 

 or some of them reduced, concave to the rhabdome, the distal part of long ones 

 often curved in the opposite direction, when fully developed, 250-285 p. long; 

 clade-angles 100-118°. Anaclades: mostly triaene, sometimes diaene or mon- 

 aene, rhabdome over 1 mm. long, 5-12 p thick; a protuberance on the apex 

 of the cladome, sometimes elongated to form an epirhabd 56-75 long; clades 

 15-30 p long; clade-angles 40-65°. 



Large choanosomal oxyasters: from four to ten, usually seven rays, 0.5- 

 2 p thick and covered everywhere, except quite at the base, with spines; cen- 

 trum very small; total diameter 18-45 p. Large subcortical oxysphaerasters: 

 from sixteen to twenty-three conical, spined rays 1.1-1.4 p thick; centrum 

 4.2-6.5 p, whole aster 16-22 p, in diameter. Small dermal oxyasters and 

 oxysphaerasters: nine to eighteen spined rays, 0.7-1.5 p thick, centrum, when 

 present, up to a third or more, of the whole aster in diameter; total diameter 

 6-13.5 p. Sterrasters 76-85 by 66-73 by 50-64 p. 



Eastern Pacific. Galapagos; Duncan Island. 



