Id Spong. 
xvi r. SPONGLE. 
Pachastrella isorrhopa , n. sp., associated with an encrusting Lithistid 
and with barnacles; Kirkpatrick (28) p. 228.— Pcecillastra symbiotica, 
n. sp., living in SpongosoHtes placenta , sunk in it but not attached to its 
support: Top,sent (62) p. 13.—Amphipods {Aristias tumulus) in the oscular 
papillae of Eumastia sitiens O. S. ; Luxdbeck (38) p. 34.— Gellius com¬ 
mensal with an alga; Etheridge (14) p. 247.—The canals of Desmacella 
fortis inhabited by 6-rayed Ophiuroidea in various stages of regeneration 
following fission ; Sollas (58) p. 214.—Symbiosis of Carterius stepanowi 
Dyb. and Scenedesmus quadricauda ; Lauterborn (32) pp. 528-532, tig. 5.— 
Symbiosis of Ephydatia Jluviatilis with Cladophora spongophila ; Koorders 
(29).—A filamentous alga (? Oscillaria sponqelice) in Sponqelia diqitata , 
n. sp. ; Sollas (58) p. 221. 
(vii) Sponges as Geological Agents, FossilizatiOn.— Rela- 
tion of sponges to flints; Hanssen(18): Maddock (40). 
E. Reproduction and Development. 
(i) Germ-Cells, Fertilization. 
Maturation of the egg Sycandra [Summary and review of Maas (25) 
Zool. Rec. 1899]; Lubosch (37). — Ova of Pihabdodermella nuttingi , n. sp. ; 
Urban (64) p. 273. 
(ii) Embryology. 
(a) General Accounts.— Haller (17) pp. 62-68, fig. 74.—General 
development of a sponge ; Jordan & Heath (24) p. 21.—General embryonic 
development of sponges ; Schneider (54) pp. 178-180.—Development of 
Sycandra as a type of the Porifera; Masterman (41) pp. 105 & 106. 
Comparison of parenchymula and planula larvae [vide ii, a, ii]; La- 
meere (30).—Recent discoveries in sponge-embryology, with figures of 
the larvae of Clathrina , Leucosolenia , Sycon , Oscar ell a, and My.villa ; 
Minchin (42) pp. 811 & 812. 
(b) Early stages, larvae, and metamorphosis. —Embryos in 
Gellius luridus, n. sp.; Lundbeck (38) p. 67. 
(c) Post-Larval Development, Organogeny, —Vacant, 
(iii) Asexual Reproduction. 
(a) Fission and Vegetative Budding.— Vide Cotte (10), in 
following section. 
(b) Germinal budding.— The observations of Ijima [see Zool. 
Rec. 1901, Spong. pp. 17 & 19] give support to the former conclusions of 
Wilson, with regard to the frequent asexual origin of sponge-larvae, which 
have been the subject of adverse criticism by certain reviewers. Gemmule- 
larvae are to be distinguished from egg-larvae; the former are derived from 
undifferentiated archaeocytes, either from a single one, or from a number. 
The single cell which gives rise to a gemmule is not to be classed as an 
ovum but as a spore; the same view must be entertained regarding the 
cooperative archaeocyte. “ In the one case we have a single spore pro¬ 
ducing the individual, while in the other case several spores unite; ” 
Wilson (72). 
The gemmules of Suberites domuncula, normally destined to germinate 
and to produce new individuals of the sponge, may also multiply under 
