ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
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have the greatest bathymetrical rangeare also generally the most widely 
distributed geographically. Some range from very shallow water to 
1000 fathoms or more, and may extend into all the great oceans. Some 
species that belong to the intermediate depths, 100 to 500 fathoms, often 
have a very wide geographical range. Many of them extend to European 
waters, and some even to the Pacific. Many peculiar and conspicuous 
genera and several remarkable families are nearly or quite confined to 
the abyssal zone. The abyssal species appear in many cases to be 
capable only of very slow dispersion, as compared with shallow-water 
species. This is, in many cases at any rate, due to the fact that many of 
them do not have free-swimming larvae, but bring forth well-developed 
creeping young. In other cases the eggs are so large as to indicate that 
the larvae, when known, will be found to be unlike those of shallow- 
water species, and not free-swimming. We must therefore conclude 
that the widely diffused abyssal genera, many of which range from the 
Arctic to the Antarctic Oceans, are of very great antiquity, and that 
there has been ample time since they occupied the deep sea for the 
minor differences characteristic of species to originate in different 
geographical regions, as a result of casual variations that have been 
conserved by isolation, perhaps aided in some cases by natural selection. 
In the majority of cases Prof. Yerrill points out that there is no evident 
utility in the characters that separate one abyssal species from another 
of the same genus. Such differences as there are can hardly be of pro 
tective value in the darkness and quietness of the depth in which these 
creatures live. The author begins an account of the Starfishes of the 
area he has been studying, in the course of which he describes several 
new species. 
G-enital and Madreporic System of Regular Echinoids.* — Sig. A. 
Russo has made his observations chiefly on young stages of Echinus 
microtuberculatus and Sphserechinus granularis. The author agrees with 
Prouho that the formation of the genital cord takes its origin from the 
outer epithelial investment of the axial sinus, but he does not share 
Perrier’s views that it has any connection with the ovoid gland. The 
gonads are at first solid swellings of the genital cord. The efferent 
ducts of the gonads arise as thickenings of the outer cell-layer of the 
Anlage of the gland. The author finds that the regular Echinoids show 
so much resemblance to the Ophiuroids that he regards them as being 
their nearest allies. 
Echinoidea of Indian Seas.f — Dr. A. R. S. Anderson has a short 
report on the Sea-urchins dredged by the Indian Marine Survey. Twenty- 
five species appear to have been collected, of which two, Dorocidaris 
tiara and D. AlcocM appear to be new. The former was dredged in 
depths of 142 and 400 fathoms, while the latter came from 636 fathoms. 
Ccelentera.'’ g 
Digestion in Ccelentera. £ — Prof. S. J. Hickson has an interesting 
general survey of what is known of this subject. Attention is drawn to 
* Bull. Soc. Natural. Napoli, viii. (1894) pp. 90-109 (1 pi.). See Zool. Cen- 
tralbl., i. (1894) pp. 752-3. 
t Journ. Asiatic Soc. Bengal, lxiii. (1894) pp. 186-95. 
I Science Progress, ii. (1895) pp. 447-55. 
