xcii GENERAL SUMMARY OF SCIENTIFIC AND 



Yerrill, of Yale College, Dr. A. S. Packard, of Salem, and 

 other specialists. Immense collections of animals were 

 dredged, many new to science, and much practical informa- 

 tion relating to the food of fishes obtained, aside from the 

 more immediate objects of tlie Commission. Many natu- 

 ralists, mostly professors of colleges, availed themselves of 

 the great advantages presented by this school of science, as 

 it practically is, and the effect of the Commission upon the 

 educational interests of the country will be widely felt. 



Coming now to the lowest organisms, we w^ould advert to 

 a memoir laid before the Berlin Academ}^, in which the ven- 

 erable Ehrenberg gives the results of his microscopical studies 

 since 1836. He intimates that the distribution of warm and 

 cold currents is now beginning to be understood, while the 

 dispersion and relative abundance of deep-sea life, and the 

 formation of silicious and calcareous ooze and muds, need 

 much more study. "VVe know not, he says, what forms of 

 being, minute or gigantic, exist throughout the abyssal 

 depths. The abundant occurrence oi Feridinia in the flints 

 of the deep-sea chalk, as well as the living luminous animals 

 on the ocean's surface, and even at the deep bottom oflfFlorida, 

 point to a possibly periodic and even permanent strong light 

 in those depths, enabling the creatures of the great deep to 

 have the use of their visual organs. 



Our knowledge of the Sponges lias been greatly advanced 

 by the great work of Haeckel on the Calcareous Sponges, in 

 three octavo volumes, and also by the papers of Carter, Sars, 

 Wyville Thomson of the Challenger^ and others. Several 

 new and interesting forms have been obtained by the United 

 States Fish Commission in deep water off the coast of Maine, 

 among them the glass-sponge, or Ilyalonema longissimiim of 

 Sars, heretofore found only in deep water off Norway. 



It is well known that certain sponges by boring into shells 

 absorb their substance, and cause them to rapidly disinte- 

 grate, until the shell is destroyed. Such is, for example, 

 Cliona celata of the Eno-lish coast, which attacks the ovster 

 shell, and, after having absorbed the whole valve, grows into 

 a shapeless mass. Another sponge, Halichondria suherea, 

 Johnst., is a species which attacks univalve shells, but often 

 retains more or less of the outward form of the shell, and 

 almost always that of the internal cavity ; for a hermit crab 



