SPONGIIDA. 
19 Sjpong. 
identical with Lefroyella decora, Wyville Thomson.] Various localities 
in Caribbean Sea, llG-878 fath. 
Calcarea. 
Moihmsisi)ongia[Mcehiisp-\ Duncan, (3) p. 378. Based on M. parasitica, 
id. 1. c. p. 377, pi. X. Found within chambers of the Foramiuifer Car- 
2 )enteria rhapJiidodendrum, from Mauritius, and described as parasitic 
there ; probably a composite A scon form ; exists in a sac-like form ; a tri- 
radiate and other spicules were observed in connection with it. 
General Anatomy and Physiology. 
O. Schmidt, in “ Die Absonderung und die Auslese im Kampf urns 
Dasein,” Kosmos, iv. p. 329, discusses the genealogy of the Lithistiidoi, 
deriving the Rhizomorina from the Tetracladina, and finding, in the 
mutual relationship of genera in this group, in the adaptation of the 
rooting apparatus of many Sponges to the nature of the bottom on which 
they grow, and in the readiness with which spicular forms, especially in 
the Hexactinellida, can be referred to common types, good arguments for 
the Darwinian hypothesis. 
F. M. Balfour, Q. J. Micr. Sci. xx. p. 247, “ On the Structure and 
Homologies of the Germinal Layers of the Embryo,” discusses the rela- 
tions of Sponges, among the other groups of the Animal Kingdom, to the 
germ-layer theory. Cy. also id. tom. cit. p. 381, “Larval Forms: their 
Nature, Origin, and Affinities.” 
Schmidt considers that the terms ‘individual’ or ‘ person,’ as applied 
to Sponges, are inadequate and meaningless : (9) p. 89. 
According to the same author, a radiate structure, as described by 
Selenka, is no new thing in Sponges, but it has no special importance : 
(9) p. 90. 
The ciliated larvae of Sponges are interpreted by Kent, (G) p. 177, as 
being %gongQ-gemmides, and as consisting, in the later planular stages — at 
least in Grantia comjjressa — of oval aggregations of collared monads, with 
their mouths directed outwards, a view which he considers to receive 
unintentional support from Barrois & Hackel’s observations. The so- 
called ova are retrograde collar- bearing zooids, and form the gemmules 
by fusion with other similar zooids. The ciliated chambers are produced 
by segmentation of a primitive amceboid zooid. A comparison is set up 
between the Sponges and the Myxomycetes in their various stages and 
structures ; 1. c. p. 192. A Choano-Flagellate Infusorian, allied to 
Phalansterium , appears to approach the Sponges very closely. 
F. E. Schulze, (11) p. 437, has been led to the belief that both the 
collar-cells of the ciliated chambers, and all the flat-celled ciliated epithelial 
coverings of the internal cavities and canals of that stage of Sponges 
which follows the sac-like embryo, are derived from the larval endoderm. 
In Placina monolopha (vide supra), the pavement epithelium of the 
outer surface is ectodermic up to the edges of the pores and vents ; the 
tissues included between the endoderm and ectoderm are mesodermic. 
The adult Sponge in all stony and siliceous Sponges hitherto investigated 
by him may be referred to a simple sac-like form, in which the ciliated 
