236 



GEODIA HILGENDORFI. 



Geodia cooksoni (Sollas). 

 Lendenfeld, Tierreich, 1903, 19, p. 115. 



Cydonium couksoni Sollas, Rept. voy. "Challenger," 1888, 25, p. 255. 



The following description is based on an examination of part of the type 

 specimen in the British Museum. 



Probably lobose. In spirit : light brown. 



Choanosomal amphioxes: 1.2-2 mm., mostly 1.7-1.9 mm. by 18-36, mostly 

 25-32 (Sollas, 1888, 41 p.). Minute dermal rhabds: mostly amphiox, rarely 

 with one or both ends blunt; 150-190 pt (Sollas, 1888, 129 n) by 2-5 //. OrtJio- 

 plagiotriaenes: rhabdome 1.2-1.9 mm. by 40-60 n (Sollas, 1888, 64.5 /<); clades 

 concave to the rhabdome throughout their length, 200-340 p long; clade-angles 

 88-104°, on an average 97°. Mesoproclades (Sollas, 1888, protriaenes): rhabd- 

 ome 1.6-2 mm. (Sollas, 1888, 2.38 mm.) by 7-13 n (Sollas, 1888, error, 75 /i) 

 at cladome and 10-18 p in the middle ; rarely three fully developed clades, usually 

 one, two, or all three reduced or absent altogether, fully developed clades 27- 

 45 fi long; clade-angles 34-64°, on an average 44°; epirhabd 30-70 p long. 



Large choanosomal oxyasters, with from two to thirteen usually strongly 

 spined, straight, conical rays, 1.6-2.3 /i thick at the base; centrum small or ab- 

 sent; total diameter 22-42 p. (not mentioned by Sollas, 1888). Sollas, 1888, 

 describes chiasters 19.7 p. in diameter with slender, cylindrical, truncate rays, 

 which were not observed by me. Oxysphaer asters: with from eleven to thirty 

 conical, distally sparsely spined rays, 0.5-1.6 p thick at the base; centrum 

 1.3-3 p, whole aster 12-18 p (Sollas, 1888, up to 19 p) in diameter. Strongylo- 

 sphaerasters: with from ten to thirty cylindrical or cylindroconical, truncate rays, 

 0.5-1.1 p thick; centrum 1.5-2.5 p, whole aster 4-6.5 p (Sollas, 1888, 1-6 p), in 

 diameter. Sterrasters: flattened ellipsoids, 75-80 /( by 70-75 p by 57-60 p 

 (Sollas, 1888, 77.4 by 66 ;0- 



Eastern Pacific. Galapagos ; Charles Island. 



Geodia hilgendorfi Thiele. 

 Zoologica, 1898, 24, p. 8, plate 1, fig. 4, plate 6, fig. 4a-k. Lendenfeld, Tierreich, 1903, 19, p. 1 12. 



Massive elongate, with broad and low lobose protuberances. Dry; whitish. 



Large amphioxes: 1.2-1.6 mm. long. Minute dermal amphioxes: blunt, 

 140-180 p long. Orthoplagiotriaenes: rhabdome 1.6-1.7 mm. long sometimes 

 reduced and rounded; clades 250-300 p long; cladome sometimes very irregular. 

 Mesoprotriaenes: rhabdome 1.2-1.6 mm. long; clades as long as or longer than 

 the epirhabd. Anatriaenes. 



