STUDIES IN SPICULE FORMATION. 155 
21. LisperKiiun, N.—“ Beitrage zur Entwicklungsgeschichte der Spongillen,” 
‘Arch, Anat. Physiol. J. Miller,’ Hefts iv, v, 1856 (monaxons of 
Spongilla arise each in one cell). 
22. Maas, O.—“-Ueber die Entwicklung des Siisswasserschwammes,”’ ‘ Zeit. 
wiss. Zool.,’ Bd. 1, 1890 (monaxon of Spongilla in one cell). 
23.. ~ “ Die Metamorphose von Esperia lorenzi, etc.,” ‘ Mitth. Zool. 
Stat. Neapel,’ Bd. x, 1892 (the cells associated with the anisochele of 
the rosettes described—probably incorrectly). 
24. “Ueber Entstehung und Wachstum der Kieselgebilde bei Spon- 
gien,’ ‘SB. Akad. wiss. Miinch.,’ Bd. xxx, 1900 (development of 
spherasters, chiasters, and tylostyles of Tethya lyncurium incor- 
rectly described). 
25. Ripuey, 8. O., anp Denny, A.—‘“‘ Challenger” Report, vol. xx, “ Mona- 
xonida,” 1887 (monaxonid spicules described as originating each in 
one cell; toxa of Esperella simonis and anisochela of Cladorhiza 
inversa so figured). 
26. Scumipt, O.—Spongien des adriatischen Meeres,”’ I Supplement, Leipzig, 
1864 (development of spicules of Reniera sp.). 
27. 
‘Zool. Ergeb. d. Nordenfahrt,’ 1872 (chelee, sigmas, and ortho- 
dragmas of Esperella lucifera described as arising each in one 
cell)... 
28. Scuuize, F. E.—“ Untersuchungen tiber den Bau und die Entwicklung 
der Spongien: die Familie der Chondroside,” ‘ Zeitschr. wiss. Zool.,’ 
Bd, xxix, 1877 (stellate spicules of Chondrosia). 
29. “Unter., ete.: Neunte Mitt; die Plakiniden,” ‘ Zeit. wiss. Zool.,’ 
Bd. xxxiv, 1880 (monaxon and calthrops of Plakina described as 
originating in one cell). 
30. “Unter., etce.: Zehnte Mitt; Corticium candelabrum, O. 
Sch.,” ‘Zeit. wiss. Zool.,’ Bd. xxxv, 1881 (calthrops of Corticum in 
one cell). 
3l. 
“ Wissenschaftliche Ergebnisse der Deutschen Tiefsee-expedition 
auf dem Dampfer ‘ Valdivia,’ 1898-1899: Hexactinellida,” Bd. iv, 
1904 (scleroplasm in connection with hexasters of Trichasterina 
borealis). : 
32. Sottas, W. J.—‘‘ The Sponge Fauna of Norway, etc.,” ‘Ann. Mag. Nat. 
Hist.’ (5), vol. v, 1880, pp. 130, 241, 396, 401 (one-cell origin of the 
trichites of Stelletta normani, the sterrasters of Geodia barrett 
and the spherasters of Isops phlegrei). 
