STUDIES ON THE COMPARATIVE ANATOMY OF SPONGES. 141] 
4. Harcxet.—‘ Die Kalkschwamme.’ 
5. Hinpe.—‘ Notes on Fossil Calcispongiw, with Description of New 
Species,” ‘Annals and Magazine of Natural History,’ vol. x, ser. 5, 
p. 185. 
DESCRIPTION OF PLATE 13, 
Illustrating Dr. Dendy’s paper ‘ On the Anatomy of 
Lelapia australis.” 
Reference Letters. 
a. Large oxeote spicules. &. Long slender oxeote spicule. c. Small oxeote 
spicules (‘‘ Mortar-spicules”). d. Tuning-fork-shaped triradiates. e. Normal 
sagittal triradiates. f Laterally extended sagittal triradiates. g. Quadri- 
radiate. d.c. Dermal cortex. d. ¢. Dermal tuft of triradiates and slender 
oxea. ex.ap. Openings of exhalant canals into central gastral cavity. 
ex. c. Exhalant canal. i. Spicular fibres formed of tuning-fork-shaped 
triradiates. g.c. Gastral cortex. osc. Osculum. s. g. s. Subgastral sagittal 
triradiates. 
(The spicules are delineated in blue throughout.) 
Fie. 1.—Lelapia australis. (From a sketch by Mr. H. J. Carter, 
F.R.S.) 
Fic. 2.—lIsolated spicules, from a preparation boiled out with caustic 
potash. Only the two ends of the large oxeote (a) are drawn. All are drawn 
to the same scale, under Zeiss C, ocular 2, camera. 
Fic. 3.—Skeleton arrangement, as seen in a thick, unstained, longitudinal 
section. x 25. 
Fig. 4.—Portion of the gastral cortex and adjacent skeleton of the 
chamber-bearing layer, as seen in a thick, unstained, longitudinal section. 
Drawn under Zeiss C, ocular 2. 
Fic. 5.—Portion of a subgastral sagittal triradiate, showing its relation to 
a very slender fibre formed of tuning-fork-shaped triradiates. Drawn under 
Zeiss C, ocular 2. 
Fic. 6.—Portion of a transverse section, stained with borax carmine and 
cut by the paraffin method. x 25. Each flagellated chamber is represented 
by a red spot. 
