AND PHYSIOLOGY OP THE SPONGIADHl. 
1135 
cloacal column, exhibiting the mode of the radiation of the distal ends of the 
small pedicels on the inner surface of the dermis, x25 linear: page 1105. 
Fig. 6. TetJiea Lyncuriimi. Section at right angles to the surface, exhibiting the corym- 
bose mode of expansion of the radial fasciculi of the skeleton near the surface 
of the sponge, X 50 linear: page 1106. 
Fig. 7. Dictyocylindrus ramosa. A section through the axial column, showing the elongo- 
reticulate structure of the skeleton of the sponge, x50 linear: page 1108. 
Fig. 8. Diploclemia vesicula. A small portion of its compound reticulate skeleton, 
exhibiting the intermixture of the spiculo-reticulate skeleton with the hetero- 
spiculate fibrous one, Xl08 linear: page 1117. 
PLATE LXXIV. 
Fig. 1. PhaJcellia ventilahrum. A longitudinal section of one of the primary radial 
lines of skeleton structure, exhibiting the slender secondary radiation of the 
skeleton, x50 linear: page 1108. 
Fig. 2. Microciona atrosangidnea. Exhibiting the columnar structure of the skeleton, 
X 108 linear: page 1109. 
Fig. 3. Hymedesmia Zetlandica. Exhibiting the disjoined fasciculi of the skeleton in 
situ, X 108 linear: page 1110. 
Fig. 4. Halicnemia 'patera. A portion of a section at right angles to the surface, exhi- 
biting the mode of disposition of the spicula of the skeleton, X 25 linear : 
page 1107. 
Fig. 5. A portion of the same section, taken at «, fig. 3, Xl08 linear: page 1107. 
Fig. 6. Hymeniacidon caruncula. Exhibiting the dispersed condition of the skeleton 
spicula on the interstitial membranes of the sponge, X 108 linear : page 1111. 
Fig. 7. HalicJiondria incrustans. Exhibiting a better type of the skeleton structure of 
the genus than Halichondria panicea, X 50 linear: page 1113. 
Fig. 8. Isodictya Normani. Exhibiting the regular and nearly rectangular structure of 
the network of the skeleton of spicula, Xl08 linear: page 1114. 
Spongilla. Agrees perfectly in the structure of the skeleton with Isodictya, 
but is distinguished from that genus by the peculiarities of the reproductive 
organs. See figures oi Isodictya, Plate LXXIV. fig. 8, page 1115. 
Fig. 9. Spongia. Showing the irregularity of the disposition of the keratose fibre, 
X50 linear: page 1119. 
Fig. 10. S'pongionella. Exhibiting the nearly rectangular mode of disposition of the 
primary and secondary keratose fibres of the skeleton, x 50 linear : page 1119. 
Fig. 11. Ilalispongia. Showing one of the large primary keratose fibres, containing 
siliceous spicula, and the irregular system of small aspiculous keratose fibres, 
Xl75 linear: page 1120. 
7 p 
MDCCCLXII. 
