clxxviii GENERAL SUMMARY OF SCIENTIFIC AND 



Anions: new text-books, Professor Carus's "Ilandbuch der 

 Zoologie " is completed by the issue of the second part of 

 the first volume, containing a part of the Vertebrates, and 

 the Mollusca and Molluscoida. In this country two excellent 

 smaller text-books have appeared, Professor Tenney's " Ele- 

 ments of Zoology," and Professor Morse's " First Book of 

 Zoology." The " Arctic Manual " is full of new matter re- 

 lating to the natural history of Greenland. 



"Life-histories of Animals, including Man," is the title of 

 an elementary manual of comparative embryology, by Dr. 

 A. S. Packard, Jr. It is reprinted in part from the Ameri- 

 can Naturalist. 



The most valuable aid to the working zoologist is the 

 "Zoological Record," the volume for 1873 having appeared 

 during 1875. 



Professor Huxley has proposed a new classification of the 

 Animal Kingdom, based on Haeckel's ; while Giard, of 

 France, has proposed some changes, the necessity of which 

 future studies must determine. For example, he unites the 

 annelides Sagitta and the Hotifera with the Mollusca. Dr. 

 Dohrn has suggested classifying the ascidians with the true 

 fishes, w T hile Giard thinks that they should be placed near 

 Amphioxus (the lancelet). 



The year 1875 has been prolific in speculative essays result- 

 ing from embryological and histological studies in connection 

 with the evolution hypothesis, guesses being published which 

 it will take decades of work to prove or disprove. 



Beginning now with the lowest forms of life, and ascend- 

 ing to the vertebrates, it is now thought by Professor Wy- 

 ville Thompson that the bodies occurring in Bathybius, and 

 also in Globigerina ooze, to which the names of "Coccoliths" 

 and " Rhabdoliths " have been applied, are probably either 

 alga? of a peculiar form, or else the reproductive gemmules 

 or sporangia of some minute plant. 



From observations made by different exploring parties, it 

 seems to be a matter of fact that the Radiolaria or Foram- 

 inifera, as well as the diatoms, inhabit the ocean all the way 

 to the bottom; i. <?., that all the calcareous shells forming the 

 ooze at the bottom have not fallen down from the surface. 

 Several new American rhizopods have been described by 

 Professor Leidy. 



