770School Science an& /l&atbematfes

Department of Zoology:NOTES.

The departmental editor in zoology accepted the responsibilities indi-cated by his title, sometime last summer. Thus far he has not receivedanything to edit or review and has had no time in which to prepare ma-terial of his own. He now appeals to all who are interested in seeing theJournal become as helpful to teachers of soology as if is to those in otherfields, to come to his assistance by the contribution of articles of a moreformal nature, or of notes on laboratory or field methods or on usefulliterature. He will be glad to receive any suggestions as to any specialtopics or field of zoology on which anyone would like to have articlesprepared. If anyone has a question of which the answer would be likelyto be of general interest send it along.

Professor C. F. Hodge of dark University has recently contributedtwo articles on biological instruction, which are of interest to teachersin that field. Dynamic Biology and its Relations to High SchoolCourses, is the title of one article and Dynamic Biology in the College,of the other. They appeared in the Pedagogical Seminary, September1904 and June, 1905.

Professor Hodge also has an article in The Country Calendar forNovember, which describes the drumming of the ruffed grouse andwhich is accompanied by reproductions from a remarkable series ofphotographs of a bird "caught in the act." This bird was one whichhad been reared from the egg and was so tame that it would drumreadily and repeatedly without regard to the proximity of the photog-rapher. From the concluding paragraphs of the article we quote thefollowing statement: "we are warranted in concluding that the drummingof the ruffed grouse is made solely by the wings striking the feathercushions of the sides, that it is purely a mate call, and that the reactionis definitely inherited."

Dr. R. M. Yerkes, of the Harvard Psychological Laboratory, contri-buted to the July number of the Journal of Comparative Neurology andPsychology the results of his recent investigation of the sense of hearingin frogs. Those who have noticed in the laboratory the unsatisfactoryevidence, given by the frog, of stimulation by noises, will be interested inthe writer’s conclusion that sounds alone never cause motor reactions;but when accompanied by visual or tactual stimuli sounds reinforce thevisual or tactual reactions. Such reinforcement does not occur whenthe auditory nerves are cut. It therefore appears that a fairly well de-veloped sense of hearing is present.

Kongi, Fysiografiska Sallskapet Handligar, N. F., Bd. 16, has two re-cent articles by Dr. Hans Wallengren which contain matter of interestto zoology teachers who make use of fresh water mussels in the labora-tory. Zur Biologic der Muschein I, Die Wasserstromeengen, has 62pages of text, 3 plates and several text figures devoted to a study of the

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afferent and efferent currents of water in certain species of Unio Ano-donta, Mytilns, Mya and Qstrea. By means of ingenious apparatus, de-scribed in detail in the text. Dr. Wallengren was enabled to reach quitecertain conclusions concerning the variability in the strength of such cur-rents under different conditions.

The apparatus included a pendulum of aluminium wire suspendedfrom a horizontal axis which was supported by needle points. The lowerpart of the pendulum which was immersed in the water containing thespecimen was hammered thin in the direction in which it would affordthe least resistance in moving through the water. To its lower end wasattached a thin plate placed transverse to the current of water issuingfrom the cloacal opening of the specimen studied. Through a slit in thewall of the pasteboard box by which the outfit was protected from cur-rents of air, a beam of light from an incandescent bulb, (placed outsidethe box) and condensing lens was reflected from a mirror attached to thehorizontal axis. The beam of light was received on bromsilvergelatinpaper stretched on a revolving drum; the light passing through a slit inthe zinc plate case by which tl^e drum was enclosed.A comparison of the path of the ray of light on the sensitive paper,

made when the pendulum was acted on by the current, with one madewhen the pendulum was at rest, made known the presence or absence ofvariations in the strengeth of the current

As results of his numerous observations made in different ways theauthor concludes among other things that in the mussel which is com-pletely at rest (unstimulated) the current flows with uniform strengththough with slight regular waves due to the movements of the. heart.Irregularities or stoppage in the current are due to muscle contractionsand are always the result of stimuli. The efferent and afferent streamsare so interdependent that any alteration in one is correlated with a cor-responding alteration of the other. The pallial dilation of the infrabranchial chambers is not a factor in producing the afferent and effer-ent currents but they are produced in the main, by the cilia of the inter-mamental canals and the pallial cilia of the supra branchial chambers.When the valves of the shell are closed, there is a water circulation keptup between the infra and supra-branchial chambers.

The second paper, Zur Biologie der Muschein II. Die Nahrungsauf-nahme, is of similar volume and deals with phenomena of alimentation.It is in this connection that the pallial ciliation of the infra-branchialchambers is chiefly involved.