StONGliE. 
S Spofig . 
The pores arise from metamorphosed collar cells, for which the name 
“Metschuikolf ’s cells” is proposed, and which reach to the exterior 
and become perforated. The granules in the Metschuikolf ’s cells 
and in the ectoderm are excretory. The nucleus of the ovum of 
Ascetta clathrus contains a typical reticulum, with small granules at 
the nodes. The rod-like bodies observed on the gastral surface of 
Sollas’s membrane in L. tripodifera are probably of vegetable origin. 
[See Dendy (4).] 
Dendy (1) describes the anatomy of Grantla lubyrinthica. The 
osculum becomes enormously wide during growth of the Sponge, so that 
the adult form consists essentially of a thin walled cup or basin. The 
wall of the cup, which in the young Sponge is simple, becomes convoluted 
and folded on itself. The cup is attached by a cylindrical stalk, not 
present in the very young Sponge. The inner surface of the cup has a 
minutely punctate appearance, owing to the openings of the flagellated 
chambers. The outer surface bears the pore sieves. The spicules are 
triradiate, quadriradiate, and uniaxial. A dermal skeleton forms a dis- 
tinct cortex on the outer surface of the Sponge, and a gastral skeleton 
forms a similar cortex on the inner side. The skeleton of the peristome 
forms an oscular fringe. The tubar skeleton is articulate. The stalk 
has a skeleton composed of a confused mass of closely interwoven 
sagittal triradiates. The pores are arranged in sieves lying between the 
ends of the flagellated chambers. In the pore areas the cortex is reduced 
to a thin membrane. The inhalant canals commence as widely expanded 
cavities under the pore sieves. They branch and anastomose, and rapidly 
diminish in diameter as they penetrate between the flagellated chambers, 
ending just below the gastral cortex. The prosopyles are regularly 
scattered over the chambers. The flattened epithelium of the inhalant 
canal meets the lining of collared cells of the chamber round the aperture 
of the prosopyle. The flagellated chambers have the usual Sycon 
character. At their peripheral euds they exhibit a marked inclination to 
branching. Structures are often met with in sections, which suggest 
that the chambers die, like individuals, and are probably replaced by new 
chambers. The exlialant canals are short, wide, cylindrical tubes, 
placing the chambers in communication with the gastral cavity through 
the cortex. They are marked off by sphincter diaphragms from the 
chambers. The ectoderm consists of a single layer of flat polygonal 
epithelial cells, with a nucleus surrounded by granules. The endoderm 
consists of flattened cells lining the gastral cavity and exhalant canals, 
and of collared cells in the chambers. The author maintains the 
existence of Sollas’s membrane, which von Lendenfeld had tried to 
deny. In the present Sponge the collars and flagella were found 
retracted, which is probably a periodically recurring phase in the 
life-history of the cells. The collared cells are narrowed towards 
the upper end, which contains the nucleus. The apices are connected 
by a fine sharp line in section, which is Sollas’s membrane, visible 
even when the collars are retracted. The mesoderm contains (1) amoeboid 
