_Amphioxi_ (adj. Rod-like spicules sharp at both ends.

_amphioxous_)

_Amphistrongyli_ (adj. Rod-like spicules blunt at both ends.

_amphistrongylous_)

_Basal membrane_ A h.o.r.n.y, structureless membrane found at the base of some sponges.

_Birotulate_ (subst. or adj.) Spicule with a transverse disk at both ends.

_Bubble-cells_ Spherical cells of the parenchyma the contents of which consist of a drop of liquid covered by a thin film of protoplasm.

_Ciliated_ (or _flagellated_) A cavity lined with collar-cells.

_chamber_

_Collar-cell_ (_choanocyte_) Cell provided at one end with a membranous collar and a vibratile lash or flagellum that springs from within the collar.

_Derma_ or _ectodermal layer_ A layer of flat cells arranged like a pavement on the surface of the sponge.

_Exhalent_ (or _efferent_) A tubular ca.n.a.l through which water _ca.n.a.l_ pa.s.ses from a ciliated chamber towards the osculum.

_Fibres_ (skeleton) Thread-like structures that compose the skeleton of the sponge and are formed (in the Spongillidae) mainly of overlapping spicules.

_Flesh-spicules_ Microscleres (_q. v._) that lie free in the parenchyma and the derma.

_Foramen_ An orifice of the gemmule.

_Foraminal tubule_ A h.o.r.n.y tube that surrounds the foramina of some gemmules.

_Gemmule_ A ma.s.s of cells packed with food-material, surrounded by at least one h.o.r.n.y coat, capable of retaining vitality in unfavourable conditions and finally of giving origin to a new sponge.

_Green corpuscles_ Minute green bodies found inside cells of sponges and other animals and representing a stage in the life-history of an alga (_Chlorella_).

_Inhalent_ (or _afferent_) A tubular ca.n.a.l through which water ca.n.a.l pa.s.ses from the exterior towards a ciliated chamber.

_Megascleres_ The larger spicules that (in the Spongillidae) form the basis of the skeleton of the sponge.

_Microscleres_ Smaller spicules that lie free in the substance or the derma of the sponge, or are a.s.sociated with the gemmule.

_Monaxon_ (Of spicules) having a single main axis; (of sponges) possessing skeleton spicules of this type.

_Osculum_ An aperture through which water is ejected from the sponge.

_Oscular collar_ A ring-shaped membrane formed by an extension of the derma round an osculum.

_Parenchyma_ The gelatinous part of the sponge.

_Pavement layer_ Adherent gemmules arranged close together in a single layer at the base of a sponge.

_Pneumatic coat_ A h.o.r.n.y or chitinous layer on the surface of the gemmule containing air-s.p.a.ces.

If these s.p.a.ces are of regular form and arrangement it is said to be _cellular_; if they are minute and irregular it is called _granular_.

_Pore_ A minute hole through which water is taken into the sponge.

_Pore-cell_ (_porocyte_) A cell pierced by a pore.

_Radiating fibres_ Fibres in the skeleton of a sponge that are vertical or radiate from its centre.

_Rotula_ A transverse disk borne by a microsclere.

_Rotulate_ (subst. or adj.) Spicule bearing one or two transverse disks.

_Spicule_ A minute mineral body of regular and definite shape due not to the forces of crystallization but to the activity of the living cell or cells in which it is formed.

_Spongin_ The h.o.r.n.y substance found in the skeletal framework and the coverings of gemmules of sponges. Structures formed of this substance are often referred to as _chitinous_.

_Subdermal cavity_ A cavity immediately below the derma (_q. v._).

_Transverse fibres_ Fibres in the skeleton of a sponge that run across between the radiating fibres.

_Tubelliform_ (of spicule) Having a straight shaft with a transverse disk at one end and a comparatively small k.n.o.b-like projection at the other.

SYSTEMATIC LIST OF THE INDIAN SPONGILLIDae.

[Types, schizotypes, or cotypes have been examined in the case of all species, &c., whose names are marked thus, *.]

Genus 1. SPONGILLA, Lamarck (1816).

Subgenus A. EUSPONGILLA, Vejdovsky (1883).

1. ? _S. lacustris_, auct. (perhaps in N.W. India).

1_a_. _S. lacustris_ subsp. _reticulata_*, Annandale (1907).

2. _S. proliferens_*, Annandale (1907).

3. _S. alba_*, Carter (1849).

3_a_. _S. alba_ var. _cerebellata_, Bowerbank (1863).

3_b_. _S. alba_ var. _bengalensis_*, Annandale (1906).

4. _S. cinerea_*, Carter (1849).

5. _S. travancorica_*, Annandale (1909).

6. _S. hemephydatia_*, Annandale (1909).

7. _S. crateriformis_* (Potts) (1882).

Subgenus B. EUNAPIUS, J. E. Gray (1867).

8_a_. _S. carteri_ var. _mollis_*, nov.

8_b_. _S. carteri_ var. _cava_*, nov.

8_c_. _S. carteri_ var. _lobosa_*, nov.

9_a_. _S. fragilis_ subsp. _calcuttana_*, nov.

9_b_. _S. fragilis_ var. _decipiens_, Weber (probably Malaysian, not Indian).