clii GENERAL SUMMARY OF SCIENTIFIC AND 



moners described by Haeckel, the minute AmcEbse may prove to be 

 young ActinoiDhrys. Should these observations be confirmed, Mr. 

 Fullagar has, perhaps, discovered the mode of reproduction by en- 

 cysting and the formation of motile Amoeba-like young, which has 

 not yet been observed in this animalcule. He also describes the 

 formation of young Actinophrys by self-division. Two modes of 

 reproduction, then, seem to be established one by encysting and 

 the other by self-division. Graef had noticed previously the multi- 

 plication of the sun-animalcule by self-division, and Schneider had 

 also seen them encyst themselves in the autumn, and the small Acti- 

 nophrys come out of the cyst in the spring. 



In sjjecial groups of animals, beginning with the lowest, we have 

 fresh information regarding the foraminifera, or lower shelled rlii- 

 zojDods. One of these animals, the Glohigerina^ has at length been 

 seen by the Challenger party with its " pseudopodia," or thread-like 

 extensions of the body, spreading out in the water. Professor Wy- 

 ville Thompson states that if a specimen be immediately transferred 

 from the tow-net to some fresh sea-water, and be examined with a 

 high power, the " sarcodic contents of the chambers may be seen to 

 exude gradually through the pores of the shell, and sjDread out un- 

 til they form a gelatinous fringe or border around the shell, filling 

 up the spaces among the roots of the spines, and rising up a little 

 way along their length." It will be remembered that the dead 

 shells of these foraminifers accumulate in such immense quantities 

 as to form modern chalk at great ocean dejDths. 



The sponges are now recognized as a distinct sub-kingdom of an- 

 imals by Huxley, Macallister, and Hyatt. Their embryology has been 

 restudied with great thoroughness by Barrois, a French observer, 

 who, with F. E. Schulze, acknowledges the presence of three germ- 

 layers, and confirms the embry logical observations of Haeckel. 



Professor Hyatt's "Revision of the North American Poriferse" is 

 the first installment of a series of papers on our native sponges, com- 

 prising considerable work done under the ausjiices of the United 

 States Fish Commission, as well as on specimens from the diflfer- 

 ent museums of the country. It is accompanied by a plate drawn 

 on stone, and contains remarks on foreign species. 



While the sponges are thus taken from the Protozoa on the one 

 hand, and the Polyps on the other, and regarded as representatives 

 of a distinct sub-kingdom, Professor E. Van Beneden, in his elabo- 

 rate " Recherches sur les Dicyemides, survivants actuels d'un Em- 

 branchement des Mesozoaires," proposes a new sub-kingdom of 

 animals. In 1830 Krohn observed the presence in the liquid bath- 

 ing the spongy bodies (perhaps renal organs) of different species of 

 cephalopods certain filiform bodies, covered with vibratile cilia, and 

 resembling infusoria or ciliated worms. They were called Dicyema 

 by Kolliker, who, with others, considered them as intestinal worms. 



