MEETINGS OF SOCIETIES. 331 
author states that these barrier-reefs have evidently been formed 
during a period of upheaval. and that the intervening channels re- 
present belts of detritus upon which the reef-building corals could 
not live; and he arrives at the conclusion that in the case of reefs 
which possess such a gradual slope that the lower margin of this 
band of detritus lies within the zone of reef-building corals, a line 
of barrier-reef will be ultimately formed beyond this band with a 
deep channel inside; but that in the case of reets which possess a 
more rapid sub-marine slope, so that the lower limit of the band 
of detritus extends far beyond the depths in which the reef corals 
thrive, no such barrier reef will be tormed. He also thinks it pro- 
bable that coral reefs may commence to build in depths greater 
than those usually assigned. 
2. ‘** Record of an undescribed Correa from New South Wales,” 
by Baron F. von Mueller, K.C.M.G., F.R.S., &c. In this paper is 
described a new species of Correa, approaching C. lawrenciana from 
the Clyde River district, collected by Mr. Wilhelm Baeurlen, and 
named after him, C. baeurlenii. Asa supplement to this, a further 
list of northern plants of New South Wales, lately discovered in 
southern districts, has been added by the author. 
3. “On Volcanic Activity on the Islands near the North-East 
Coast of New Guinea, and evidence of Rising of the Maclay 
Coast in New Guinea,” by N, de Miklouho-Maclay. The author, 
during his stay at the Maclay Coast in 1871 and 1872, recorded 13 
shocks of earthquake; and on asubsequent visit, in 1876, he found 
that the country had suffered great devastation by tidal waves. 
The disturbances he attributed to volcanic eruptions on some 
islands about 20 miles distant from the mainland. The land had 
evidently been elevated to a height otnearly 1000 feet, as deposits 
of recent shells were found at about that elevation. 
4. ‘* Note on a Beroid of Port Jackson,” by R. von Lendenfeld, 
Ph.D. The subject of the paper, Nets cordigera, Lesson, was 
described from a specimen captured in Port Jackson in 1824 by 
the naturalists of the Coquille, and there is no record of its having 
ever been seen since until a few weeks ago. Weis represents a genus 
quite distinct from Bevoe. Its sexual cells are matured in the vas- 
cular reticulation exclusively, to which place the ova migrate from 
the meridional canals. The style cells described as sensitive ele- 
ments by B. Hertwig and Chun are considered by the author to be 
poisoning thorns. 
5. “The Histology and Nervous System of the Calcareous 
Sponges,” by R. von Lendenfeld, Ph.D. The new facts mentioned 
by the author relate chiefly to the structure of the spicules and 
nervous system of sponges. The spicules are invested by a meso- 
dermal cuticule extending over the protruding portion, outside of 
which there is a layer of cells. The spicules themselves are.com- 
posed of minute prisms. The nervous system consists of mesoder- 
mal spindle-shaped sensitive elements and multipolar ganglion 
cells. These are not present in the Asconide and Homodermide 
(new fam.). In Sycones they form rings or separate bunches around 
the inhalent pores. In Leucones they are either solitary or in 
bunches scattered irregularly over the outer surface. Gland cells 
in Hetevocelia are described. 
6. *‘ Addenda to the Australian Hydromeduse, No. 2,” by R. von 
Lendenteld, Ph.D. This paper treats of some recently established 
