SCIENCE. 



[Vol. XXII. No 544 



Limncea. Again, Mr. W. Dolierty. writing from Cincinnati, 

 records a remarkable dentate variety of Conulus fulvtis ; lie fur- 

 ther remarks that dentate species of Helix are the forms there 

 prevalent, and points out that this formation is useful in ob- 

 structing the entrance of a grub which lives in beds of leaves and 

 preys on small snails. 



An American malacologist, Professor Wetherby, adduces evi- 

 cence which goes far to prove that even malformations resulting 

 from individual injuries may, under certain circumstances, be 

 transmitted to the offspring. 



In investigating these phenomena and their causes, I would 

 suggest, first, that the manner of variation should be investigated 

 and described, and, second, the exact nature of the surroundings 

 as regards possible causes, always bearing in mind the conditions 

 under which the species lives in its original home, and especially 

 noting all deviations from these which may be supposed to in- 

 duce the varietal character. 



Among the species common to North America and Britain are 

 the following: Vertigo alpestris, V. edentula, Conulus fulviis, 

 Helix aspersa, H. hortensis Limncea peregra, L. auricularia, L. 

 ■stagnalis, L. palustris, L. tnmcatula, Physa fontinalis, Bullinus 

 hypnonim, Planorbis albiis (= P. hirsutus, Gould), P. glaber 

 {= P. parvus, Say). W. A. Gain. 



Tuxtord, Newark, England. 



Books for Children. 



In answer to Mr. Waldo's request printed under the above 

 heading in your issue of Science for June 16, let me suggest that 

 such books as he desires are a desideratum not only for children, 

 but for adults who, while not scientifically inclined, are yet in- 

 terested in the wonders and beauties of nature. Unfortunately 

 our attention has been too exclusively absorbed with the strug- 

 gles and the problems incident to a new country for us to have 

 time to educate the men who could study and name all our 

 plants and animals, much less those who could translate scien- 

 tific monographs into popular language. Especially in the insect 

 world a good collector could bring in from any summer-day's 

 excursion dozens of specimens which have never yet been christ- 

 €ned. 



But while we cannot hope for books which will enable us to at- 

 tach names to everything we may find in a ramble through Na- 

 ture's museum, most of the more conspicuous animals and plants 

 have been studied, at least enough for this purpose, though the 

 results have been put forth ia scientific works. But on the 

 stores of knowledge thus accumulated popular writers are begin- 

 ning to draw to meet the demand created by our growing out- 

 of-door life, our increased out-of-door interests. As was to be 

 expected, plants have received the greater amount of attention. 

 Mrs. William Starr Dana's "How to Know the Wild Flowers," 

 just pubHshed by Charles Soribner's Sons, at |l..50, is intended 

 to teach one to identify the commoner fiowers by color, size and 

 shape of leaf, size of plant and so forth. Ten-year-old children 

 ■would seem to me rather young to use such a book, but it is ad- 

 mirable for those of twelve or thirteen. Newhall's "Trees of 

 Northeastern United States," published by G. P. Pjtnam's Sons, 

 at $2, teaches one to identify trees by the leaves, bark, and 

 so forth. This I know from experience to be admirable for 

 children. The same author is at work on a similar book upon 

 shrubs, but I believe it is not yet out. I know of no such book 

 on birds as the ones I have just suggested on plants. The best 

 thing for children I believe to be Florence Merriam's "Birds 

 through an Opera Glass," published by Houghton, Mifflin & Co., 

 at 75 cents. The appendix to this little book contains lists giv- 

 ing form, color, size, habits, song, flight, nest, and so forth of 

 ■our common birds. A fuller and altogether admirable book on 

 birds is Minot's " Song and.Game Birds of New England," pub- 

 lished, I believe, by Casino, at |2.50 or %'i. The best book on in- 

 sects is one which Professor Conistock, of Cornell University, has 

 in hand. It will probably be out now in the course of a very few 

 months. Prepared especially for the school children of Califor- 

 nia, it is written in a manner attractive to children and will con- 

 tain tables by which any insect may be traced to its proper fam- 



ily. Farther than this it would be hardly possible for a child to 

 go, as the characteristics on which genera and species are founded 

 are often so difficult of observation that the best tables which 

 could be prepared would be only a source of perplexity and 

 worry. 



After all the best method of teaching children is that which Mr. 

 Waldo quotes as employed by his former teacher. And there 

 are many books which occur at once to the mind of any teacher 

 as valuable aids to the parent who w ishes to work with his child. 

 I have not named these because I understood the request to be 

 for books which the child could use alone. But 1 should be 

 happy at some future time to extend my list if it is not done by 

 some other person better qualified for the task. 



M. A. WiLLCOX, 

 Professor of Zoology, Wellesley College. 



Tvico Queries. 



• An incident of a recent personal experience may interest those 

 of your readers who are studying the subject of mimicry. On 

 the 21st of May last, I was botanizing with two companions in 

 the thinly populated sand-dune region at the south end of Lake 

 Michigan, and about forty miles east of Chicago, when the event 

 I am about to relate occurred. I was walkingrather in advance 

 of my companions across a level area that separated two series 

 of high dunes, when I accidently stepped upon two large snakes 

 which were lying close together, doubtless enjoying the warm 

 sunshine. It was a case of mutual surprise, and as the snakes, 

 or one of them, suddenly sprang upvpard into unpleasant prox- 

 imity to my face, I only a little less suddenly siirang backwai-d, 

 believing for the instant that I had encountered a rattlesnake. I 

 soon discovered, or thought I did, that the reptiles were only fine 

 specimens of the kind of black snake, popularly called the blue 

 racer. One of the two had been considerably hurt by my heavy 

 tread, and with violent contortions of his body made what haste 

 he could to a hole about six feet distant, and disappeared in it. 

 The other was uninjured and crawled rather leisurely away in 

 another direction to a distance of twenty feet or more, and then 

 lay quiet, watching our movements. Irritated by the violent 

 start I had received, and cherishing no great love for snakes in 

 general, I seized a club, and, while his suakeship lay broadside 

 to me, I aimed a vigorous blow at him. I was again surprised, even 

 more so than before, though in a different way, for with light- 

 ning rapidity the lithe reptile dodged the blow which otherwise 

 would have struck him near the middle of the body, and instant- 

 ly threw himself into a coil precisely resembling that of a rattle- 

 snake when about to strike, and shook his erected tail with such 

 vigor and rapidity that it was scarcely more distinctly visible 

 than the spokes of a bicycle wheel when propelled by a fast rider. 

 At the same time a sound was emitted, less shrill perhaps, but 

 continuous and distinctly similar to that produced by the rattle- 

 snake. Whether the sound was produced by the very rapid vi- 

 bration of the tail, assisted perhaps by its scaly covering, or 

 whether it was a hiss produced in the ordinary manner, I am of 

 course unable to say. So close was the mimicry that I was for 

 the moment almost deceived into the belief that I had mistaken 

 a rattlesnake for a racer. The illusion was soon dispelled how- 

 ever, for a stick which I threw at'him hit him on the head and 

 stunned him, and I then had the opportunity to scrutmize him 

 closely and verify my first conclusion. 



I have frequently heard of other constrictor snakes mimicking 

 venomous ones, in fact have occasionally observed such mimicry 

 myself, but never before in this species and never in such perfec- 

 tion. It would be interesting to know if others have observed 

 the habit in this species. 



On the same trip another fact of interest came under our ob- 

 servation. The region visited contains many ponds and lagoons, 

 and in these turtles (mainly Chrysemys picta, Ag. and Nanemys 

 guttatus, Ag.) abound. About these ponds, often many rods from 

 the water, were the remains of hundreds of turtles that had evi- 

 dently all been killed since the opening of the spring, and some 

 of them within a few hours. The dead turtles varied in size from 

 those with carapaces two inches long to those fully six inches in 



