The hexactinellid sponge collected aboard FORV Sagar Sampada from the eastern side of North Andaman waters at 13^o06' N lat. and 93^o11'E long. was identified as Hyalonema (Cyliconema) apertum apertum. This species, collected at a depth of 402 m, belonged to the Class Hexactinellida, Order Amphidiscosida and Family Hyalonematidae. The body is spindle-like, followed by basalia in the form of long twisted spicules. Identical specimens collected from 12^o57' N lat. & 93^o07' E long. and 12^o45' N lat. & 93^o09' E long. confirmed the presence of H. (Cyliconema) apertum apertum in the Central Andaman waters too. The present communication describes the characteristic features of H. (Cyliconema) apertum apertum along with a detailed account of the types and dimensions of spicules.

Deep-sea sponge, Hexactinellida, Hyalonema, Andaman waters