A guide to the deep-water sponges of - NMFS Scientific Publications ...

48 Professional Paper NMFS 12
32. Polymastia pacifica Lambe, 1893
Description. This sponge is subglobular to cushionshaped.
Surface is smooth to the unaided eye but
microhispid with several papillae. Consistency is firm.
Diameter is to at least 15 cm. Externally it is brownish orange
in color; internally it is bright orange with lighter
polyspicular tracts visible to the unaided eye.
Skeletal structure. Ectosomal palisade of small tylostyles
are supported by intermediate tylostyles. Large
tylostyles radiate in polyspicular tracts to the surface.
There are large tylostyles (up to 4400 × 20 µm), intermediate
tylostyles (200–600 × 12–16 µm), and small
tylostyles (120–160 × 5–7 µm).
Zoogeographic distribution. Uncommon. North
Pacific Ocean. In Alaska – central Aleutian Islands.
Elsewhere – previously reported from Vancouver Island
to California.
Habitat. In Alaska – attached to pebbles at depths
between 150 and 160 m. Elsewhere – 73 m depth (Vancouver
Island). Lamb and Hanby (2005) report that
this species occurs from Alaska to California at depths
between the intertidal zone and 183 m.
Photo. 1) Fragment of a specimen collected at a depth
of 155 m in the central Aleutian Islands. Grid marks are
1 cm 2 .