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ARTHUR DENDT. 
EXPLANATION OF PLATES XXX, XXXI, XXXII, & 
XXXIII, 
Illustrating Mr. Arthur Dendy’s paper, “ Studies on the Com- 
parative Anatomy of Sponges/’ II, “ On the Anatomy 
and Histology of Stelospongus flabelliformis. Carter; 
with Notes on the Development.” 
(The following Explanation of llie Lettering applies to all the Figures.) 
a. c. Amoeboid cell in the embryo, c. Collar of collared cell. c. c. Collared 
cell. c. e. 1. Cell of external layer (ectoderm) in the embryo, cli. Choano- 
some. col. Collum or neck of collared cell. eg. Cystenckyme. e. Embryo. 
e. c. Embryo capsule, e. c. c. Exbalant cameral canaliculus, eel. Ectosome. 
e. 1. Exbalant lacuna, e. 1. c. External layer of cells (ectoderm) of the em- 
bryo. e. o. exbalant opening of flagellated chamber, f. Skeleton fibre. 
f . Skeleton fibre projecting at the surface of the Sponge, f. c. Flagellated 
chamber, fl. Flagellum of collared cell. g. Granule on the margin of the 
collar of the collared cell. i. c. c. Inhalant cameral canaliculus, i. 1. Inha- 
lant lacuna or channel, i. o. Inhalant opening of flagellated chamber, m. c. 
Mesodermal cell. n. Nucleus, n. c. c. Nucleus of collared cell. n. e. c. 
Nucleus of epithelial cell. nut. c. Nutrient epithelial cell from the lining of 
the embryo capsule, nut. e. Nutrient epithelium from the lining of the 
embryo capsule, o. Osculum. o. t. Oscular tube. p. Pore. p. a. Pore- 
area. p.f. Primary fibre of skeleton, pt. Pit or depression on the surface 
of the embryo, caused by a nutrient epithelial cell. r. b. Deeply staining, 
radiately fibrous, globular bodies of unknown function, probably parasitic 
organisms, r. m. Reticulate membrane in flagellated chamber, Sollas’s mem- 
brane. s. f. Secondary fibre of skeleton, s. g. Sand grain, spb. Spongo- 
blast. st. c. Stellate cell in the embryo. 
PLATE XXX. 
Stelospongus flabelliformis. 
Fig. 1. — Specimen of Stelospongus flabelliformis, from which a 
portion of one side has been cut off. Natural size. 
Fig. 2. — Outer portion of a section at right angles to the surface of the 
Sponge, showing the relations of the ectosome (eel.) to the ckoanosome (eh.), 
and the proximal portions of the inhalant canal system commencing with the 
pores (p.). 
Fig. 3. — A small portion of the skeleton, showing the primary fibres (p.f.) 
and the secondary fibres ( s.f ). 
