340 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
Development of Septa of Halcampa chrysanthellum.* * * § — M. Faurot 
describes the order of development of the twelve large septa of Halcampa 
chrysanthellum ; they are arranged in pairs, and are fertile in their upper 
part only. The smaller septa, of which there are twelve also, are all 
sterile. 
Habits and Species of Tubipora-f — Dr. S. J. Hickson sometimes 
found a lump of Tuhipm’a half in and half out of the water ; in such 
cases every stage of contraction may be seen. It is very probable that 
the power of complete retraction into solid calcareous tubes enables the 
organ-pipe coral to live in places which are at times left partially dry 
at low w'ater. The author was forced to conclude that only one true 
species is to be found at Talisse. The length and diameter of the tubes 
and the appearance of the horizontal platforms are not the trustworthy 
specific characters which they have been supposed to be. The length 
and diameter depend entirely upon the position of the coral on the reef. 
Maturation of Ovum and Early Stages in Development of Allopora.f 
— Dr. S. J. Hickson finds that, while ova and young embryos are found 
in the younger branches of the colony, the sperm-morulae and spermatozoa 
are only found in the older, thicker branches. As an ovum growing in 
one of the ordinary canals enlarges it pushes out the endoderm and 
ectoderm of the canal in which it is formed, and thus makes for itself a 
diverticulum ; at the same time the endoderm of the eanal-wall in the 
immediate neighbourhood of the aperture of the diverticulum becomes 
thickened, and throws out five radial pouches which embrace the proximal 
pole of the diverticulum. The five pouches throw out secondary pouches 
and give rise to a nourishing lenticular mass of cells — the trophodisc. 
A little later, and after some changes, fertilization probably occurs. 
The primitive ectoderm arises in the form of a thin membrane of clear 
protoplasm containing only a few small yolk-spherules which separates 
from the distal periphery of the young embryo. This ectoderm spreads 
over the periphery until it entirely incloses the central protoplasm and 
yolk-mass, and the embryonic ectoderm-cells are formed by the splitting 
up of the protoplasm into columnar epithelial cells, each of which con- 
tains a single nucleus. When the embryo has a complete columnar 
ectoderm it is ready to escape, but the method by which this is effected 
has not yet been observed ; probably a channel is formed for it by the 
absorption of a part of the superjacent calcareous skeleton. 
Occurrence of Hydromedusae and Scyphomedusae throughout the 
Year.§ — Prof. W. C. MHntosh gives interesting notes on this subject, as 
a further contribution from the St. Andrews Marine Laboratory. The 
Medusae are of importance to fisheries, owing to the vast number of ova 
and free planulae to which they give rise. 
Mode of Attachment of Embryos to Oral Arms of Aurelia aurita.|| 
— Mr. E. A. Minchin, finding that the only descriptions of the brood- 
capsules of this common Jellyfish — those of Claus and Agassiz — are 
* Comptes Reudus, cx. (1890) pp. 249-51. 
t ‘ A Naturalist in North Celebes ’ (London, 1889) pp. 128-30. 
X Quart. Journ. Micr. Sci., xxx. (1890) pp. 579-98 (1 ph). 
§ Ann. and Mag. Nat. Hist., v. (1890) pp. 296-306. 
II Proc. Zool. Soc., 1889 (1890) pp. 583-5 (2 pis.). 
