74 BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



lands in 8 to 10 meters, and Doderlein's at Thursday Island. The 

 type-locality is not known. 



ASTROPECTEN MONACANTHUS Sladen. 



Astropecten monacanthus Sladen, 1SS9, p. 216, pi. 33, figs. 7 and 8; pi. 37, 

 figs. 10-12.— KoEHLEB, 1910a, p. 37, pi. 3, figs. 9-11 ; pi. 5, fig. 11.— Dodeb- 

 LEiN, 1917, p. 150, pi. 14, figs. 5-5b ; pi. 17, fig. 9. 



Eight specimens from the following localities: 



Station 5181, off eastern Panay, 26 fathoms, mud, fine sand; 2 

 specimens. 



Station 5182, off eastern Panay, 24 fathoms, mud, fine sand; 1 

 specimen. 



Station 5480, vicinity of Surigao Strait, 62 fathoms, fine sand; 2 

 specimens. 



Station 5481, vicinity of Surigao Strait, 61 fathoms, sand, shells, 

 gravel; 2 specimens. 



Mantaquin Bay, Palawan, 4 feet, sand, 1 specimen. 



Type-locality — East of Panay, Philippine Islands, 20 fathoms, 

 mud (C'AaZZen^er expedition). 



Distribution. — Philippine Islands, Andaman Islands, east coast of 

 India, Eed Sea. 



Remarks. — The largest specimen measures R=37 mm., r=10 mm.; 

 the smallest, E=15 mm., r=5 mm. The 3 examples from stations 

 5181 and 5182, east of Panay, are practically from the type-locality. 

 These conform to the figures and description given by Koehler of 

 large specimens, and there seems to be no doubt that his examples are 

 true monacanthus. Sladen's type is a rather small specimen. 



The largest specimen, from station 5181, has a small tubercle on 

 one of the first inferomarginal plates. The color is a light dull 

 brown, with the center of disk and a narrow radial stripe reddish 

 brown. 



Astropecten monacanthus is readily recognized by its fairly large 

 paxillae, unarmed granulate supermarginals (the granules flattened 

 and sometimes squamiform), the close mail of rounded imbricating 

 inferomarginal squamules, the single flattened to subterete lateral 

 spine, with a small companion just below it, and the highly charac- 

 teristic adambulacral armature. The latter consists of 3 flattened 

 furrow spines truncate or round tipped, the median with edge to 

 furrow. These are succeeded by 2 narrow flattened subambuhicral 

 spines, so placed as to appear to form an arc of 5 with the furrow 

 spines. They are shorter than the lateral furrow spines, usually 

 tapering and bluntly pointed. Commonly only the aboral one is 

 present. Back of these are 2 very broadly spatulate round-tipped 

 or truncate spines, about as long as the lateral marginal spines, the 

 tiboral slightly the larger. Sometimes the aboral member of the 



