168 REPORT OF NATIONAL MUSEUM, 1889. 



public and by students interested in this branch of natural history. 

 The economic exhibit contained separate series, each being devoted to 

 a particular species, including - insects that feed upon the different 

 grains, the cotton plant, the apple, the grape, and the various species 

 of ornamental and forest trees. It was prepared for the benefit of the 

 agricultural classes, and contained specimens and drawings illustrating 

 the development of the various species, their methods of feeding, and 

 samples of roots, stalks, branches, leaves, flowers, and fruits that had 

 been injured by them. The descriptive label accompanying each speci- 

 men contained information of practical value to the farmer and fruit- 

 grower, and suggested methods by which they could to a greater or less 

 degree protect their crops from the ravages of these pests. 



SECTION OF MOLLUSKS. 



The Department of Mollusks in the Museum forwarded a collection, 

 prepared by Dr. W. H. Dall and Prof. R. E. C. Stearns. The object, 

 as in the case of the other natural history collections, was to illustrate the 

 principles on which the present system of classification was based. 

 The exhibit, though occupying only about 250 feet of floor space, was 

 very complete, and contained specimens representing all of the impor- 

 tant families of marine mollusks not only of this country, but of other 

 parts of the world. JSTo attempt was made to show the laud shells, as the 

 time was too short to get up a collection, and there was not sufficient 

 space for displaying the same, even if it had been prepared. 



SECTION OF MARINE INVERTEBRATES. 



A collection of marine invertebrates was prepared by Mr. F. A. Lucas, 

 osteologist of the Museum. It consisted of a carefully selected series of 

 typical representatives of the various families of sponges, corals, jelly- 

 fishes, echinoderms, and star-fishes. As a rule, the species were repre- 

 sented by dried and carefully mounted specimens of the animals them- 

 selves ; but such groups as could not be preserved in this way were 

 shown by means of glass models obtained from Europe. The collection 

 of sponges contained full series of both the ornamental and commercial 

 species of our own country and a number of the more important com- 

 mercial species from the Mediterranean Sea. The families of corals 

 were represented by numerous species from the offshore banks of the 

 North Atlantic, by a number of the more attractive forms from the Gulf 

 of Mexico, and by a collection of the typical forms from Polynesia. 

 The growth of the red or precious coral of commerce was shown by 

 means of models. The exhibit illustrating the families of jelly-fishes 

 was made up exclusively of glass models, by means of which a number 

 of the more delicate forms, including the Portuguese man-of-war, were 

 represented. 



SECTION (IF BOTANY. 



The botanical exhibit was prepared by Mr. F. H. Knowlton, Assist- 

 ant Curator of Botany. It consisted of a collection of chromolitho- 

 graphs of the flowering plants and ferns of the country, and of an ex- 



