314 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
three united to form a single triradiate system ; (c) to some of these 
a fourth ray was added ; ( d ) some of the triradiate systems became 
secondary monaxons. 
In Leucosolenia all the dermal cells may form monaxon sclerites, 
and this is the more primitive condition ; in Clathrina , however, the 
skeletogenous cells migrate from the dermal epithelium inwards, and 
form a connective tissue layer. 
The forms of the spicules are the result of adaptation to the re- 
quirements of the sponge as a whole, produced by the action of natural 
selection upon variation in every direction. 
Fibres of Reniera.* * * § — Dr. G. Loisel has studied the fibres of Beniera , 
(a) in the living sponge, ( b ) after use of Congo red, and (c) with the 
usual reagents. He worked with B. ingcdli and B. elegans. 
The substance composing the fibres reacts like spongin, but this is 
a wide word. The material appears inside spherular spongoblasts, 
which are in some regions isolated, in others grouped irregularly or in 
a necklace-like row. in the centre of each cell, beside the nucleus, a 
small refractive sphere is seen ; this grow’s into a little rod : adjacent 
rods touch and fuse, being cemented by a plasmic substance. The 
spongoblasts elongate and fuse, and are then disintegrated, their nuclei 
being left in the semi-fluid surrounding substance. Thus the whole 
process is essentially very simple, and is all the more instructive as a 
subject of study that it continues throughout the life of the sponge. 
Parenchyma-Spicules of Spongiilidse.j — Herr Fr. Fetr concludes 
that the scattered parenchyma-spicules, as opposed to the united skeletal 
spicules, are important only in relation to the gemmules. They form 
an accessory skeleton to the gemmules, and lie on the surface of the 
chitinous membranes. The author describes them as migrating and 
grouping themselves around the young gemmules, accessory to the 
amphidiscs, &c. 
Zanzibar Sponges. J — Prof. R. von Lendenfeld describes about a 
dozen new species from Zanzibar, including two new genera Sirongy - 
lacidon in the family Esperellidm, and Axinyssa in the family Axi- 
nellidae. 
Protozoa. 
Amoebae from a Medical Point of View.§ — Dr. R. Behla has written 
a little book on Amoebae, especially in connection w T ith diseases, such as 
dysentery. 
Myxosporidia in Coregonus.|] — Herr F. Zschokkc has studied these 
parasites, which occur in the connective tissue of the musculature in 
Coregonus , and have been referred by Gurley to three different species. 
To Zschokkc they all seem the same, and he proposes the new name M. 
bicaudatus to supersede the older titles. The species is characterised by 
the unusually large size of the cysts and the length of the double tail 
process on the spores. 
* Journ. Anat. Physiol., xxxiv. (1898) pp. 1-43 (1 pi. and 7 figs.). 
t Zool. Anzeig., xxi. (1898) pp. 226-7. 
X Abh. Senckenberg. Nat. Gesell., xxi. (1897) pp. 93-133 (2 pis.). 
§ ‘ Die Amoben, insbesondere von parasitaren und eulturellen Standpunkt > > 
Berlin, 1898, 73 pp., 1 pi. || Zool. Anzeig., xxi. (1898) pp. 213-4. 
