38 SCIENCE. 



in teaching, and is not likely to get from any other source. The illus- 

 trations are remarkably clear and suggestive ; but, to teach the pupil 

 the value of personal observation and a correct habit of study, nothing 

 can take the place of specimens. It is desirable that those who are to 

 use this Guide shall be able to refer to No. IV. of this series, which is 

 frequently quoted. 



A Set of Twenty-four Specimens, to accompany Guides IV. 

 and V., will be furnished for $2.00. 



Mollnsca. Oyster, Clam, and Other Common Mol- 



lusks. (No. VI) By Aitheus HYATT. Illustrated with 17 plates, con- 

 taining jj figures. 4J4 by 6 inches. Paper. 65 pages. Introduction 

 price, 25 cents. 



This book not only holds in compact form all that need be taught 

 beginners about the oyster, clam, and other common mollusks, but is 

 invaluable as illustrating in detail the natural method of teaching. 

 From first to last, the pupil is a discoverer ; the teacher is simply the 

 guide, — the pupil is self-taught. The author condescends to the 

 simplest things, and tells in the plainest way just how to lead the class 

 to make, in proper order, the necessary investigations and discoveries. 

 The most inexperienced teacher will be able, with this manual, to give 

 these lessons with success. 



A Set of Seventeen Specimens to be used in giving the lessons 

 outlined in Guide No. VI. will be furnished for $1.00. 



Worms and Crustacea. (No. VII.) 



By Alpheus Hyatt. Illustrated. 4% by 6 inches. Paper. 68 pages. 

 Introduction price, 25 cents. 



The space given to 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 cultivating the habit of close 

 observation. The specimens needed for the lessons upon worms are 

 the common earthworms and the Neresis. In these lessons, as in the 

 preceding, the children are to be discoverers, not mere learners, — they 

 are to be taught by experience the value and the pleasure of direct per- 

 sonal observation. 



