320 G. C. J VosMAER, 
addition to those which form the skeleton proper. Consequently it 
is necessary to compare skeletal preparations with ordinary sections, 
in which, however, a great part of the spicules are broken by the 
process of sectionising. It is evident that the skeletons prepared in 
the way mentioned above, first have to be studied in toto; but in 
the second place portions of it have to be mounted in balsam. If 
the spicules or some of the spicules are very large, it is difficult to 
get a fair idea of the maximal size as they easily break. In Ras- 
pailia, e.g. the greater part of the projecting styles turn out to be 
broken in mounted specimens. 
References. 
1758. SEBA, A., Locupletissimi rerum naturalium thesauri etc., III. 
1767. Linn£, C. v., Systema naturae, Ed. 12. 
1794. ESPER, E. J. C., Die Pflanzenthiere, II. 
1828. FLEMING, J., A History of British Animals. 
1833. NARDO, G. D., in: Isis (Oken). 
1862. BOWERBANK, J. S., in: Philos. Trans. R. Soc., CLI. 
1862. SCHMIDT, O., Die Spongien des adriatischen Meeres. 
1866. —-, Zweites Supplement der Spongien des adriatischen Meeres. 
1867. Gray, J. E., in: Proc. Zool. Soc. London. 
1868. WRIGHT, E. P., in: Proc. Irish Acad., X. 
1870. EHLERS, E., Die EspEr’schen Spongien. 
18800. SCHMIDT, O., in: Arch. microsc. Anat., XVII. 
1881. VOSMAER, @. C. J., in: Nederl. Staatscourant, No. 109. 
1884. Riptey, S. O., in: Rep. Zool. Coll. “Alert”. 
1885. ‘CARTER, :H. J., in: Ann. Mag. N. H. (5), XV. 
1887«@. DENDY, A., in: Ann. Mag. N. H. (5), XX. 
1887. RıpuLEy, 8. O. & A. Denpy, in: Challenger Reports, Zool., XX. 
1890«. ToPsENT, E., in: Bull. Soc. Zool. France, XV. 
1894. HANnITSCH, R., in: Trans. Liverpool Biol. Soc., VIII. 
18948. ToPsenT, E., in: Revue Biol. Nord France, VII. 
1896. DEnpy, A., in: Proc. R. Soc. Vietoria (2), VII. 
1905. —, in: Rep. Pearl Oyster Fisheries Manaar, Suppl. X VIII. 
1905. Pıck, F. K., in: Arch. Naturgesch. 
19118. VOSMAER, @. C. J., in: Siboga-Expeditie, Porifera, p. 1—69, 
Pl. I-XIV. 
