CLASSIFICATION OF HYALONEMA
Phylum :- Porifera (Pore bearing cellular grade, asymmetrical or radially symmetrical.)
Class :- Hexactinellida (Glass sponges with siliceous spicules of triaxon or six-pointed type.)
Order :- Amphidiscophora (Hexaster spicules absent and amphidisks present.)
Habit and habitat
- Hyalonema is marine animal, found 60 to 95 fathoms deep.
Distribution
- Found along new England coast.
Characteristics of Hyalonema
- Commonly called as glassrope sponge.
- Body is spherical or ovoidal and axially traversed by a bundle of long spicules.
- Spicules are often fused to form a lattice-like skeleton, giving the sponge a glasslike appearance when dried.
- Glass sponges are most symmetrical and most individualized. Body is cup or vase-shaped measuring 10 to 30 cm in height. Spongocoel is well developed. Osculum contains sieve plate.
- Stick or-columella is composed of a root tuft or root spicules which acts as hold fast organ.
- Root spicules are compact, stalklike elongated, twisted and giving the appearance of a rope. The middle columella contains symbiotic polyps (Epizoanthus).
- It possesses large and small amphidisk spicules like fresh-water sponges. Entire body contains small, branching, six-rayed spicules resembling Christmas trees on cross-shaped bases.
- When the upper surface of the sponge is depressed, spongocoel is formed and excurrent canals open into it but when columella is projected into gastral cone, no spongocoel exists. osculum body symbiotic polyps root spicules
- Flagellated chambers are arranged radially and in parallel planes in the sponge wall.
Identification of Hyalonema
- Since the specimen has glossy root tuft, large osculum, ostia symbiotic polyps and all above features hence it is Hyalonema.
Instructions : Study and draw root spicules stalk, body, ostia and symbiotic polyps compare the morphoanatomical features of Leucosolenia, Sycon, Euplectella and Hyalonema.