622 



SCIENCE. 



[Vol. II., No. 40. 



than in adjacent parts of the chromosphere, hut not 

 at all in the cloud-cap. The magnesium members of 

 the b group showed the cloud faintly in the same 

 way as the sodium-lines; but in b.^ the form was a 

 little more conspicuous. 



Between b and F, two lines (A .5017.6 and 4923.1, 

 both attributed to iron) showed the cloud-cap as 

 beautifully as either of the two below C. Numerous 

 other lines were reversed in the chromosphere, but 

 none of them showed tlie upper parts of the promi- 

 nence, i'' appeared much the same as D.,. 



Between Fand G,five lines were noted as showing 

 the cap. The most refrangible of them was Loren- 

 znni's/(A 4471.2): the other four I did not identify 

 at the moment, being in haste to reach the violet por- 

 tion of the spectrum, and intending to examine them 

 later, — an intention I was not able to carry out, on 

 account of the intervention of clouds. 



The lines Hy (A 4340) and h were, of course, con- 

 spicuous, each showing the whole of the prominence. 

 1 expected that H and Jt would do the same, but was 

 disappointed. They both exhibited the cloud-cap 

 finely, but I could not make out -in them either the 

 stems of the prominence, or the spikes and knots of 

 the chromosphere; and yet both the lines were well 

 reversed, not only in the chromosphere, but also on 

 the face of the sun itself, over all the faculous region 

 surrounding the spots. The ultra-violet line above K, 

 first observed here a few weeks ago, was not visible. 



There was no considerable motion-displacement 

 exhibited by any of the lines, — something rather 

 singular in so brilliant a prominence, — nor did its 

 shape cliange much during tlie forty-five minutes of 

 observation. 



It is perhaps possible that this cloud was indentical 

 with a remarkably brilliant facular bridne, which was 

 observed two days before, spanning the largest of the 

 spots which composed the group: still tliis is by no 

 means certain. The instrument employed was the 

 nine and one-half inch equatorial, with the Clark 

 spectroscope carrying a Rutherfurd grating, of about 

 17,0UO lines to the inch; .first-order spectrum. 



C. A. Young. 



Princeton, N..I., Oct. 22, 1«S3. 



Sternal processes in Gallinae. 



Having several times been asked the function of the 

 long processes of the sternum as found in the Gallinae, 

 I would make the following suggestions: — 



If the sternum be examined in situ, the outer pro- 

 cesses will be seen to extend far back, and well up the 

 sides of the body, while the inner pair extend over 

 the abdomen. The notches between the processes 

 are closed by very tense, fibrous membranes. By this 

 means a large area is afforded for the insertion of 

 muscles with a minimum of bone. This must con- 

 tribute slightly to diminish the weight of the posterior 

 end of the body. Passing now to the muscles, we 

 find that the great pectoral arises from the entire 

 posterior border of the sternum, while the subclavius 

 fills up the angle between the keel and body of the 

 bone. 



So much for the anatomy. What are tlie physio- 

 lo:.;ical results, and why could they not be attained in 

 other ways? The results are an increased amount of 

 pectoral muscle, and an increase in the length of the 

 fibres, as compared with many oilier birds. Both 

 of these are very desirable results for heavy birds of 

 short, rapid flight, — the first, because with the in- 

 crease in muscfe comes a corresponding increase of 

 force in the stroke of the wing; the second, because, 

 by virtue of the long fibres, rapidity of contraction 

 and a long stroke of the wing are secured. The rapid- 



ity is gained by all parts of the fibres contracting at 

 once, whence the longer the fibre, the more quickly 

 will a given amount of motion result. Both the 

 first and the second are also aided by the fact that the 

 first part of a muscular contraction is more powerful 

 than the last part. 



Tbere is but one other way in which tlie same re- 

 sults, so far as the insertion of the muscles goes, 

 could be attained; that is, by their origin from the 

 ribs wliicli lie under the sternum, as in the mammals, 

 instead of from the overlapping sternum. To this, 

 however, there is an all-powerful objection. If a 

 man be watched while violently using his arms, it 

 will be noticed that the upper part of the chest is held 

 stationary. The pectoral muscles must have a firm 

 point to pull from, in order to move the arms. As 

 a result, respiration in the upper part of the chest is 

 impeded, or, better, respiration is impeded by the di- 

 minished amount of tidal air. This principle is illus- 

 trated in the long, slow stroke, about twenty to the 

 minute, of men trained to row great distances. The 

 breathing is done, while the pectoral muscles are re- 

 laxed, at the normal rates. The same, only in a much 

 greater degree, would hold good for birds. Were the 

 muscles inserted into the ribs, respiration would be 

 interrupted several times each second during flight: 

 hence it is evident that the muscles could not be in- 

 serted into the ribs. 



But again: why should the Gallinae require rapid 

 powerful motions of the wings? Wliy should they 

 not have long wings, and a comparatively slow 

 stroke? This is forbidden by their habits. Long 

 wings would be very cumbersome when the bird was 

 on the ground, and absolutely worthless in much of 

 the brush through which a grouse will fly with 

 wonderful rapidity. 



Theref(u-e we may say that the processes are devel- 

 oped to give, with the greatest economy of material, 

 a large area for tlie insertion of the pectoral muscles 

 in such way as not to interfere with respiration, 

 and that such area is required for the flight of the 

 bird. J. Amojiy Jeffries. 



A bifurcate tentacle in Ilyanassa obsoleta. 



Some years ago, when collecting for my marine 

 aquarium, in Karitan Bay, at Keyport, N.J., I ob- 

 tained an Ilyanassa obsoleta of such a strange form, 

 that I made a pencil-sketch and notes of it at the 

 time. The left tentacle was bifurcated at the shoul- 

 der, or place where the normal tentacle abruptly nar- 

 rows. The two sub-tentacles thus caused, seemed 

 to be equally sensitive, as each was capable of sepa- 

 rate and independent movement. Several instances 

 have been long known to me of bifurcation of the 

 caudal spine of Limulus ; but the additional prong 

 in every instance was f unctionless, and, in fact, an in- 

 convenience. I have also seen malformed antennae 

 in microscopic insects. As I have not heard of a 

 similar instance in the mollusca, it seemed to me that 

 the case should go on record. 



Samuel Lockwood. 



Fi-celiold, N.J. 



The mechanism of direction. 

 Shortly af ler reading Professor Newcomb's paper in 

 Science for Oct. 2(5, fstio, I had the pleasure of meet- 

 ing him, and of discus«ing some matters of mutual 

 interest in regard to subjective states of conscious- 

 ness. It seems to me that the professor does not give 

 sufficient weight to habit, and to unconscious cerebral 

 action. In the strict sense of the word, one is not 

 always conxcioua of the Avay he is going; for although 

 he may avoid obstacles of any kind, yet he may pass 



