civ GENERAL SUMMARY OF SCIENTIFIC AND 



ponent of the water; this, with the pressure exercised, causes 

 a rapid solution of carbonate of lime, leaving a homogeneous 

 red mud, which in the Pacific soundings is always highly 

 charged with Polycystinm. 



A new amoeboid organism from fresh-water was described 

 by Dr. G reef, under the name of Pelobius, intended as a pair 

 to Bathybius. This name was already in use for an insect, 

 and he now proposes Pelomyxa, and he figures it in three 

 plates. The masses are large, dark brown in color, and pro- 

 truding lobose hyaline pseudopodia. 



What is a Sponge? This seems a more difficult question than 

 ever. Haeckel has recently confirmed, in a great measure, Mr. 

 Carter's view, that it is a collection of amoeba-like infusoria. 

 Professor H. J. Clark published in 1866 a paper in which he 

 maintained that the sponge was an aggregation of flagellate 

 infusoria, a compound protozoan animal. Haeckel contends 

 that the monads of Clark are simply cells, lining the general 

 stomach-cavity of the sponge; and that the sponge is not a 

 compound infusorian, but a much more highly organized an- 

 imal, allied to the radiates; and he regards the sponges and 

 acalephae as evolved from a common ancestor, which he 

 terms Protascus. 



In the April and July numbers of the Quarterly Journal 

 of Microscopical Science Professor Wright commences a 

 translation of Ernst Haeckel's " Gastrea Theory." It is a 

 remarkable paper, and will be closely studied by those inter- 

 ested in the question of development and descent. This 

 name, "Gastrea," was first applied by Haeckel, in his "Phi- 

 losophy of the Calcareous Sponges," to what he considers the 

 primitive root form, long extinct, which existed in the ear- 

 lier primordial time (Laurentian period), represented, there- 

 fore, by the Eozoon Canadense. This theory is a bold at- 

 tempt at a fundamental remodeling of the whole system of 

 zoology, and is, it is claimed, the first attempt to lead to a 

 causal knowledge of the most important morphological rela- 

 tions, and the principal typical differences in the structure 

 of animals, as well as at the same time to discover the his- 

 torical sequence of the origin of the animal organization. 

 Inheritance and adaptability are the only " two mechan- 

 ical causes" with the help of which the gastrea theory ex- 

 plains the origin of the leading natural groups of the animal 



