A NEW GENUS OF BRITTLE STARS, AMPHICONTUS 



(Plate 1) 



Alex Hill 



Research Associate, Allan Hancock Foundation 



Among the several vials of minute brittle stars from the Hancock 

 Collections given me for identification, one contained a small specimen 

 from Velero Station 384 collected in 5 fms., three fourths of a mile off 

 shore, on the east side of Independencia Bay, Peru. The conclusion w^as 

 finally reached that the species was new and that it did not belong to 

 any genus in the collection. However, the shape of the disk, the outline 

 of the plates, and the small size indicated the Amphiuridae. A sketch and 

 a preliminaiy description were forwarded to Dr. Hubert Lyman Clark 

 of the Museum of Comparative Zoology, Cambridge, Mass. 



While waiting to hear from Dr. Clark, the author found another lot 

 of brittle stars, from Velero Station 330-35. Careful examination of these 

 showed that they were essentially like the specimen from Peru, and one 

 was then foi-warded to Dr. Clark. Station 330-35 is on the south side of 

 Albemarle Island, Tagus Cove, Galapagos, in 12 fms. This stop had 

 been made by Velero III, December 12, 1935, on her way to Peru. 



Further study confirmed earlier conclusions, and Dr. Clark suggested 

 that the new genus be named Amphicontus (Amphi — in accordance with 

 the related genera — plus xoyTog — a pole, in reference to the polelike 

 spines on the disk). 



The generic diagnosis is as follows : 



AMPHICONTUS, new genus 



Amphiuridae with a thick disk covered by a large central plate sur- 

 rounded by five primary plates of equal size, accompanied by a number 

 of small scales. Radial shields large, somewhat irregularly oval, smooth, 

 in close contact with each other. Interradial areas each covered by 8-10 

 (or more) small plates and scales, three of which carry relatively big, 

 blunt, polelike spines; one of these lies close to the primary radial plates, 

 while the other two are on the interradial margin. Side armplates large, 

 bearing stout, blunt, not flattened spines of nearly equal length. Dorsal 

 and ventral armplates large, more or less pentagonal, notably similar 



^ 



