Page:The Zoologist, 4th series, vol 6 (1902).djvu/60

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animals which seem totally neglected by field naturalists. How many have observed a Starfish in the act of devouring a Mussel, of which an excellent illustration is given? (p. 241). A little practical zoology will also guide our observations and conclusions. All of us who have hunted Crocodiles will remember the sometime unpleasant proximity of the tip of snout, and that only to be seen, of one of these submerged saurians close to the small and deeply-laden canoe; but do all remember that this ruse is only possible by the fact of the choanæ or posterior nares being "situated very far back directly over the glottis, whilst the external nostril is at the tip of the snout"?

A feature in the classification is that of a large Sub-phylum of the Phylum Vertebrata, designated Craniata, distinguished by possessing a skull and brain. This is again divided into two divisions, that styled Gnathostomata including Pisces, Amphibia, Reptilia, Aves, and Mammalia. However, classifications are only propositions; but in studying these we frequently discern affinities of which we had no previous cognizance, and differences of whose existence we were ignorant. Our space debars further reference to this most interesting and important volume.

The Protozoa. By Gary N. Calkins, Ph.D.New York: The Macmillan Company.

In a hidden world—at least beyond the range of our unaided vision—live the Protozoa, unicellular organisms "not far removed from the colorless bacteria on the one hand, and the primitive green plants on the other." In the earlier works of Linnæus the existence of these animals was treated with complete scepticism, though in the later editions of the 'Systema Naturae' they were admitted under the significant generic name Chaos. Why, to-day, are these creatures so neglected by zoologists? Some are even known to menace the life of man, but it would be as difficult to find an ordinary child who was ignorant of the existence of the Tiger, as to discover one who could define what was meant by a Protozoön. The Protozoa are also of indirect injury to humanity. Among the Sporozoa the Sarcosporidiida produce morbid symptoms in domestic animals often leading to death, while