SPONGIIDA. 
503 
Miklucho-Maclay (M^m. Pdtersb. 1870) considers the pores and 
oscula of sponges homotypic structures, and that the osculum may originate 
by the union of pores or by the development of a pore. If this be the case, 
then, as Oscar Schmidt remarks {op. cit. p. 84), the whole coelenterate theory 
falls to the ground, as the mouths and cutaneous pores of coelenterate^olypes, 
with which the oscula and pores of sponges have been compared, are cer- 
tainly not homotypic or homologous structures. But Schmidt does not think 
that Maclay’s theorj' is borne out by the simplest sponges, though in Geodinse 
in some cases pores may enlarge to pseudoscula. 
Carter (Ann. N. H. (4) vi. pp. 329-341) notices in marine sponges 
{Halichondria simulans, Johnston, and Grantia nivcd) the tessellated aggre- 
gations of sponge-cells which he previously described in SpongiUa as 
ampullaceous sac,” and which he considers to be the special digestive 
organs of the sponge. Carter thinks that the sponges, as possessing distinct 
channels for excretory purposes, are more akin to the Polyzoa and Tunicata 
than to the Corals, and compares also the canaliferous structure of the 
coenosarc of compound Tunicata to the canal-system of sponges (ih. p. 336). 
Regarding the question of sexual generation in the sponges, Carter likewise 
mentions certain uniciliated bodies in Mxcrociona atrosangumea, which he 
considers may possibly be spermatozoa, and certain minute spherical cells or 
capsules in Halichondria ganicea^ possibly true sexual ova {ih. pp. 339-341). 
Lieberkuhn (Ann. N. II. (4) vi. p. 497) maintains that the contrac- 
tile substance of SpongiUa consists of independent nucleated cells, separable 
by heating the sponge to a temperature of about 140° F., and that in certain 
cases, as in the formation of the siliceous parts of the gemmules, the sponge- 
cells may reproduce the plan of the vegetable cell. [The Recorder has not 
had an opportunity of seeing the original paper on the “ Motory Phenomena 
of Animal Cells,” in Schriften Ges. Marburg, ix.] 
Vaillant (1. c.) describes two sorts of papillae in Cliona celata ; the first 
with large openings, the second more numerous, with small openings, mis- 
understood by Grant, who supposed they were a transitory state of the large 
ones. According to Vaillant the large ones are oscula, the small are pores or 
inhalant openings. 
Carter (Ann. N. H. (4) v. pp. 73-83), after comparing Gragella cya- 
thophora, Carter, and Osctdina pohjstomella^ O. Sdt., with Cliona northum- 
hrica, Hancock, comes to the conclusion that the two former are free forms of 
the Clionidoe. JRaphyrus griffithsi^ Bbk. (given by Schmidt as a synonym of 
his Tapillina suherea), he considers to bo but a free form of Cliona celata; 
Lbk. He considers {ih. p. 82) the question decided that certain sponges may 
feed on the organic matter of shell-substance, just as certain fungi feed on 
woody tissue. 
Oscar Schmidt (Spong. Atlant. p. 13) proposes the term HexactinellidcB for 
the siliceous sponges with sexradiate spicules ( Vitrecc, Wyville Thomson). In 
a second new family, Lithistidcc, the same author includes his new genera 
Leiodermatium atid Corallistes. They have a continuous siliceous skeleton ; 
but its fibres or spicules do not belong to the sexradiate type, but form an 
apparently quite irregular confused network. 
The same author {op. cit.) divides the sponges into four great divisions or 
orders, to which, however, he does not as yet give definite names : — 
I. Spicules of sexradiate type : — Hexactinellidce and (extinct) Ventriculitidm. 
