STRUCTURE OF THE LARVA OF SPONGILLA LAOUSTRIS. 463 



14. ScHULZE, F, E,— " Ueber den Bau uud die Entwickelung von Sycandra 



raphanus, llaeckel," * Zeitschr. f. wiss. Zool.,' xxv, suppl., pp. 247— 

 280, Taf. 18—21. 



15. ScHULZE, F. E.— " Ueber der Verhaltniss der Spongien zu den Choano- 



flagellaten," ' Sitzungsber. Akad. Berlin,' 1885, i, pp. 179—191. 



16. TopsENT.E.—" Notes histologiquesausujetde Leucosolenia coriacea 



(Mont.), Bow," ' Bull. Soc. Zool. France,' xvii, pp. 125—129. 



17. Wilson, H. V.—" Observations on the Gemmule and Egg Development 



of Marine Sponges," ' Journ. Morph.,' ix, pp. 277— 406, pis. xiv— xxv. 



18. Zykoff, W. — "Die Entwickelung der Gemmula bei Ephydatia fluvia- 



tilis," 'Bull. Soc. Imp. Nat. Moscow' (1892), No. 1, pp. 1—16. 



EXPLANATION OF PLATES 35—41, 



Illustrating Mr. Richard Evans' paper " On the Structure and 

 Metamorphosis of the Larva of Spongilla lacustris. 



All the figures have been drawn with the camera lucida, some of them 

 being magnified about 350, the rest 1000 times. 



SIGNIFICANCE OF THE LETTERING. 



Cavities, Canals, and Membranes. 

 C. Cavity of the flagellated chamber. D. Dermal membrane. M. Mar- 

 ginal membrane. E. C. Exhalant canal. /. C. Inhalant canal. L. C. Larval 

 cavity. 5". C. Subdermal cavity. /.«•/?. Flat epithelium. 



Cells. 

 c.c. Collar-cell, c.g.n. Cell with granular nucleus, c.v.n. Cell with a 

 vesicular nucleus. /. c. Flagellated cell. g. c. Cells of the cell groups. 

 pi. a. Plasmodial aggregation, sp. c. Spicule cell, or scleroblast. 



Nuclei. 

 g.7i. Granularnucleus. n.Jl.c. Nucleus of flagellated cells, n.g.c. Nucleus 

 of a cell of the cell groups, n. sp. c. Nucleus of spicule cell. n. c. c. Nucleus 

 of collar-cell. v. n. Vesicular nucleus. 



Other Structures. 

 c. Collar. /. Flagellum. /. c. c. Flagellum of a coUar-cell. sp. Spicule. 

 e.p. Apopyle (or exhalant chamber pore). i.p. Prosopyle (or inhalant 

 chamber pore), y. b. Yolk body. «. v. Nutritive vacuole, b. n, v. Blackened 

 nutritive vacuole. 



