344 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
West Indian Chalinine Sponges.* — Mr. A. Dendy gives an account 
of the Chalinine fauna of the West Indies ; of the eight species described 
five are new. They are interesting as exhibiting the great variability 
in external form to which species of sponges living in shallow, or com- 
paratively shallow water are subject, and they illustrate in a very 
striking way the manner in which the siliceous spicules gradually 
degenerate and ultimately completely vanish as the horny skeleton 
becomes more and more stiongly developed. This latter point has 
already been urged by the author and Mr. S. O. Ridley in their 
‘ Challenger ’ report. From the systematic point of view we are led to 
the conclusion that it is no longer possible to draw a sharp line of dis- 
tinction between the Chalininee and the so-called Keratosa. The 
immediate cause of the disappearance of the spicules appears to be the 
devefopment of spongin to such an extent as to form by itself a 
sufficiently strong skeleton ; in such forms spicules would probably be 
actually harmful as tending to make rigid and brittle fibre that should 
be elastic and flexible. Spongin appears to develope to a large extent 
only in warm climates and rather shallow waters. 
Development of Siliceous Sponges.f — M. Y. Delage asserts the 
presence of a special external cellular layer which becomes the ecto- 
derm, and of ciliated cells which represent the endoderm in the larvee of 
Siliceous Sponges. This statement disposes of the radical and incom- 
prehensible difference which has been supposed to obtain between 
Calcareous and Siliceous Sponges. Observations made on the develop- 
ment of Fissurella show that the processes of development are funda- 
mentally the same. The larva of this form may be regarded as a 
Sycon-laTYO, which, in place of being empty within, early developed a 
large amount of mesoderm which filled the whole body ; the ectoderm, 
instead of being confined to the posterior pole, extends, under the form 
of a layer of separated elements, over the whole of the ciliated region. 
As a regular invagination is made impossible owing to the presence of a 
central nucleus the ciliated cells make their way separately, breaking 
the ranks, so to speak, and later on take up their epithelial position 
within the interior of the body. 
Protozoa. 
Terricolous Protozoa.| — Dr. Maria Sacchi has a preliminary note 
on terricolous Protozoa. If a little dry earth be placed on a slide, the 
large grains eliminated, the rest moistened with a drop of distilled water, 
and the usual cover-glass laid on, there is at first no appearance of life. 
In a short time, however, there will be signs of diatoms or algae, and, 
later on, there may or may not be indications of Ehizopods and 
Infusorians. Sometimes, and especially when fragments of protozoic 
tests are seen in the earth, various forms of Amoehde may be easily found. 
The richest earths are those collected from clefts and angles of walls or 
roofs ; the poorest, compact vegetable humus. The species most frequently 
found are Amoeba princeps^ radiosa, verrucosa, terricola. Of the last a 
* Trans. Zool. Soc. Loud., xii. (1890) pp. 349-68 (6 pis.). 
t ( )oraptes Rendus, cx. (1890) pp. 654-7. 
J Journ. de Miciogr., xiv. (1890) i>p. 107-9. 
