224 



SIDONOPS ALBA. 



Sidonops californica Lendenfeld. 

 Ante, p. 18. 



Elongate, tuberous. In spirit : yellowish white. 



Large choanosotnal amphioxes: 1.2-2 mm. by 30-48 /jl. Large styles: rare; 

 55 n thick. Minute dermal styles: 175-290 by 3-7 p.. Very minute amphioxes: 

 50 by 1 /<, possibly foreign. Orthoplagiotriaenes: rhabdome 0.9-1.45 mm. by 

 20-78 /<; clades concave to the rhabdome, 160-400 /< long; clade-angles 104- 

 120°. Mesoplagioclades: rhabdome 6-15 /j. thick; from one to three clades, 

 20-42 n long; clade-angles 102-118°. Anatriaenes: rhabdome 10-17 /i thick; 

 clades stout, 22-45 jj. long, clade-angles 45-66°. Anadiaenes and anamonaenes: 

 of similar dimensions; rare. 



Large choanosomal oxyastei's: six to fourteen rays, 1.7-3 /i thick, covered 

 everywhere, except at the base with spines; total diameter 22-48 //; size in 

 inverse proportion to ray-number. Small oxysphaer asters: 7-9 /x in diameter. 

 Small strongylosphaerasters: from six to seventeen spined rays, rounded termi- 

 nally and 0.8-1.5 /t thick; centrum 2-3.5 /«, whole aster 4.5-9 //, in diameter. 

 Sterrasters: 116-130 by 97-105 by 70-90 /y. 



Eastern Pacific. West coast of North America; 22° 52' N. "Albatross" 

 Station 2829. 



Sidonops alba (Kieschnick). 



Lendenfeld, Tierreich, 1903, 19, p. 100. 



Si/nops alba Kieschnick, Zool. iur/,., 1S96, 19, p. 529. 



Sydonojis alba (Kieschnick) Thiele, Abhandl. Senckenb. gesellseh., 1900, 25, p. 46, plate 2, fig. 16a-h. 



Irregular, depressed, with attached foreign bodies. Dirty brownish white. 



Large choanosomal amphioxes: 2.5 mm. by 30 /z. Large styles: rare, of 

 similar dimensions as the Jarge amphioxes. Minute dermal styles: 250 by 

 5 /<. Plagiotriaenes: rhabdome 2 mm. long; clades 450 p. long. Mesoproclade- 

 derivates: monaene or diaene; clades reduced, short; total length of spicule 

 3 mm.; its thickness 14 /z; epirhabd 80 /i long. Large anatriaenes: rhabdome 

 2.5 mm. by 14 /<; clades, strongly recurved, about 20 p. long. Minute dermal 

 anaclades (Thiele, 1900, exotyles): triaene, or, more rarely, diaene or monaene; 

 rhabdome 170 p long and about as thick as the minute dermal styles. 



Oxyasters: a smaller kind with numerous rays, not quite up to 15 p long; 

 and a larger kind with few, rough rays, up to 30 p long. Small strongylosphaer- 

 asters : rays short and stout ; centrum large ; total diameter about 8 p. Sterr- 

 asters: 110-90 p. 



Western Pacific. Ternate. 



