ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
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nervous at all, but is analogous to the enclodermal canals of the Antlie- 
modinse, and is similarly characterised by the absence of the middle 
lamella. All such structures the author believes to be of importance 
in regulating the flow of water through the colony, and preventing 
excessive rise of pressure. 
In the swimming-bells of Pliysophora the outer surface of the velum 
and sub-umbrella is covered by ganglion-cells and nerves which con- 
stitute a nerve-plexus, but there is no ex-umbrellar nerve-ring like that of 
Medusoids. There is, however, a narrow but distinct sub-umbrellar ring, 
apart from which there are no nervous elements in the sub-umbrella. 
The nervous system of each bell seems to be connected with that of the 
stem by the “ spindle-shaped ” organ. 
In two species of ForsJcalia (F. LeucTcarti and F. Edwartsii'), distinct 
pigment-spots are present in the bells above the opening of the upper 
radial canal into the ring canal. The pigment-cells are modified glan- 
dular cells, and the author believes that the spots are not sense-organs, 
but patches of excretory substances. 
Fiji Acalephs.* * * § — Prof. A. Agassiz and Mr. A. G. Mayer describe 
the Acalephs found by them in the Fiji Islands. Altogether 38 species 
were obtained, of which 26 are new to science. With the exception of 
two Rhizostomae, all of the genera are represented by species found in 
the Atlantic Ocean, and the affinity between the Medusae of the Fiji 
Islands and those of the West Indies is remarkably close. In six cases 
they were unable to distinguish any specific differences between the 
Fijian species and well-known Atlantic forms. It is interesting to 
notice that while many characteristic types of tropical Atlantic Medusae 
are also found in the Pacific, the most eminently characteristic tropical 
Pacific forms — the Rhizostoma3 — have remarkably few analogues in the 
Atlantic. The westerly set of the great equatorial current would hinder 
the entrance of Pacific forms into the Atlantic. 
Skeleton-formation in the Anthozoa.! — Mr. G. C. Bourne has made 
an extensive series of observations on various Anthozoa, in order to de- 
termine certain disputed points as to the structure and origin of the cal- 
careous skeleton. In her paper on Madreporian Corals, Dr. Maria 
Ogilvie J stated her belief that the corallum in these corals is formed by 
certain cells — “ calicoblasts ” § — which become calcified and form the 
laminae of the skeleton. Mr. Bourne’s results lead him to the conclusion 
that the scales described by Miss Ogilvie as calcified calicoblasts are not 
cells at all, but “ crystalline growths formed by the deposition of needles 
of lime in a colloid matrix.” This colloid matrix is secreted by the true 
calicoblasts, which are quite distinct from the scales. In this matrix 
the formation of crystals occurs according to the ordinary laws of 
crystalline growth, “ but the general arrangement of the fasciculi of 
crystals is dominated, in some manner of which we are ignorant, by the 
living tissues which clothe the corallum.” The paper includes detailed 
descriptions of the skeletons of various corals and other Anthozoa, and 
is very fully illustrated. 
* Bull. Mus. Comp. Zool. Harvard, xxxii. (1899) pp. 157-89 (17 pis.). 
+ Quart. Journ. Micr. Sci., xli. (1899)pp. 499-517 (4 pis.). 
t Phil. Trans. R.S.. clxxxvii. (1896) p. 83. 
§ The proper spelling is “ chalicoblast.” — E d. 
