_To examine the capsules of the nettle-cells._--Place a living _Hydra_ in a small drop of water on a slide and press a thin cover-slip down upon it.

_To preserve freshwater polyzoa in an expanded condition._--Place the polyzoa in a gla.s.s tube full of clean water and allow them to expand their tentacles. Drop on them gradually when they are fully expanded a 2% aqueous solution of cocaine, two or three drops at a time, until movement ceases in the tentacles. Then pour commercial formaldehyde into the tube in considerable quant.i.ties. Allow the whole to stand for half an hour. If it is proposed to stain the specimens for anatomical investigation, they should then be removed through 50% and 70% to 90% alcohol. If, on the other hand, it is desired to keep them in a life-like condition they may be kept permanently in a solution of one part of commercial formaldehyde in four parts of water. Care must be taken that the process of paralyzing the polypides is not unduly prolonged, and it is always as well to preserve duplicate specimens in spirit or formalin with the lophoph.o.r.e retracted.

_To prepare statoblasts for examination._--Place the statoblasts for a few minutes in strong nitric acid. Then remove the acid with water, pa.s.s through alcohol, clear with oil of cloves, and mount in a small quant.i.ty of Canada balsam under a cover-slip, taking care that the statoblasts lie parallel to the latter.

ADDENDA.

The following addenda are due mainly to an expedition to the lakes of k.u.maon in the W. Himalayas undertaken by Mr. S. W. Kemp in May, 1911.

PART I.

Genus SPONGILLA.

Subgenus EUSPONGILLA (p. 69).

1 a. Spongilla lacustris, subsp. reticulata (p. 71).

Specimens were taken in the lake Malwa Tal (alt. 3600 feet) in k.u.maon, while others have recently been obtained from the Kalichedu irrigation-tank in the Pagnor _talug_ of the Nellore district, Madras (_G. H. Tipper_).

4. Spongilla cinerea (p. 79).

Specimens were taken in Naukuchia Tal (alt. 4200 feet) in k.u.maon. They have a pale yellow colour when dry. This sponge has not hitherto been found outside the Bombay Presidency.

Subgenus EUNAPIUS (p. 86).

8. Spongilla carteri (p. 87).

Specimens were taken in Bhim Tal (alt. 4450 feet) and Sat Tal (alt. 4500 feet). Some of them approach the variety _cava_ in structure.

Subgenus STRATOSPONGILLA (p. 100).

12. Spongilla bombayensis (p. 102).

Add a new variety:--

13 a. Var. pneumatica, nov.

(i.) The sponge forms a flat layer of a pale brownish colour as a rule with short and very delicate vertical branches.

In one specimen it takes the form of an elegant cup attached, only at the base, to a slender twig.

(ii.) The gemmules are covered, outside the spicules, by a thick pneumatic coat of irregular formation and with comparatively large air-s.p.a.ces.

(iii.) The gemmule-spicules are regularly sausage-shaped.

TYPES in the Indian Museum.

HABITAT. Naukuchia Tal (alt. 4200 feet), k.u.maon, W. Himalayas (_S. W.

Kemp_).

Genus EPHYDATIA (p. 108).

After _Ephydatia meyeni_, p. 108, add:--

Ephydatia fluviatilis, _auct._

? _Ephydatia fluviatilis_, Lamouroux, Encyclop. Method. ii, p. 327 (1824).

_Spongilla fluviatilis_, Bowerbank (_partim_), Proc. Zool.

Soc. London, 1863, p. 445, pl. x.x.xviii, fig. 1.

_Ephydatia fluviatilis_, J. E. Gray (_partim_), Proc. Zool.

Soc. London, 1867, p. 550.

_Meyenia fluviatilis_, Carter (_partim_), Ann. Nat. Hist.

(5) vii, p. 92, pl. vi, fig. 11 _a_, _b_ (1881).

_Ephydatia fluviatilis_, Vejdovsky, Abh. k. Bohm.

Gesellschaft Wiss. xii, p. 24, pl. i, figs. 1, 2, 7, 10, 14, 19 (1883).

_Ephydatia fluviatilis_, _id._, P. Ac. Philad. 1887, p. 178.

_Meyenia fluviatilis_ var. _gracilis_, Potts, _ibid._, p.

224.

_Meyenia robusta_, _id._, _ibid._, p. 225, pl. ix, fig. 5.

_Ephydatia fluviatilis_, Weltner, Arch. Naturg. Berlin, 1895 (i) p. 122.

_Ephydatia robusta_, Annandale, Journ. As. Soc. Bengal, 1907, p. 24, fig. 7.

_Ephydatia fluviatilis_, Weltner, in Brauer's Susswa.s.serfauna Deutschlands xix, Susswa.s.serschwamme, p.

185, figs. 316, 317 (1909).

_Ephydatia fluviatilis_, Annandale, P. U. S. Mus. x.x.xviii, p. 649 (1910).

[Many more references to this common species might be cited, but those given above will be sufficient.]

This species only differs from _E. meyeni_ in the following characters:--