SCIENCE. 7 



No. III. Commercial and Other Sponges. 



By Professor Alpheus Hyatt. Illustrated by; plates. Paper. 43 pages. 

 Price, 20 cents. 



Gives an account of the sponges in common use, and amply illus- 

 trates their processes of growth and the methods of obtaining them 

 and preparing them for the trade. 



No. IV. A First Lesson in Natural History. 



By Mrs. Elizabeth Agassiz. Illustrated by 40 woodcuts and 4 plates. 

 Paper. 64 pages. Price, 20 cents. 



A general history of hydroids, corals, and echinoderms, written in 

 narrative form, for very young children, under the direction of Prof. 

 Louis Agassiz. 



No. V. Common Hydroids, Corals, and Echino- 

 derms. By Alpheus Hyatt. Amply illustrated. Paper. 32 pages. Price, 

 20 cents. 



Shows how the studies, or observations, are to be most satisfac- 

 torily made, and supplies such information as one needs in teaching 

 and is not likely to get from any other source. 



No. VI. Mollusca. Oyster, Clam, and Other 



Common Mollusks. By Alpheus Hyatt. Illustrated with 17 plates, con- 

 taining 53 figures. Paper. 65 pages. Price, 25 cents. 



This book holds in compact form all that need be taught begin- 

 ners about the oyster, clam, and other common mollusks, and is inval- 

 uable as illustrating in detail the natural method of teaching. 



No. VII. Worms and Crustacea. 



By Alpheus Hyatt. Illustrated. Paper. 68 pages. Price, 25 cents. 



The description of the lobster (and fresh-water crayfish) will, it is 

 hoped, incite teachers to occupy more time in dealing with some one 

 common animal, and thus to cultivate the habit of close observation. 



