ammoniacal solution of cupric oxide be so concentrated that the whole of the rays of a less wave-length than 0.00051 mm. are absorbed, a rapid and powerful effect is produced, although the amount of heat that passes is very small. It is thus seen that the phenomena in question are not the result of heat. The next point determined by Dr. Pringsheim, is, that the effects are not produced in an atmosphere devoid of oxygen. This was the case whether the oxygen was replaced by pure hydrogen or by a mixture of hydrogen and carbon dioxide; while the removal of the carbon dioxide from atmospheric air was altogether without effect on the phenomena. The conclusion drawn is that the decomposition of chlorophyll in the living plants is a process of combustion which is influenced and promoted by the action of light, and which is not related to the decomposition of carbon dioxide by the plant. When the green color of the chlorophyll-grains has been partially destroyed, it cannot be restored, even though the cell continues to live; from which it is inferred that the result is not a normal physiological, but a pathological effect. No substance was found in the cells which might be regarded as the product of the decomposition of the chlorophyll, nor was any oil or starch detected in the etiolated cell, nor any formation of grape-sugar or dextrine. The assumption is therefore that the products of decomposition are given off in the gaseous form. The conclusion is drawn that the decomposition produced in the protoplasm, and in the other colorless cell contents, is the direct effect of the photochemical action of light. That it is not due to the injurious influence of the products of decomposition of the coloring matter of the chlorophyll, is shown by the fact that it takes place equally in cells destitute of chlorophyll, such as the hairs on the filaments of Tradescantia, the stinging hairs of the nettle, &c. It is, on the other hand, dependent on the presence of oxygen, or is a phenomenon of combustion. The results of a variety of experiments leads Dr. Pringsheim to the important and interesting conclusion that the chlorophyll acts as a protective substance to the protoplasm against the injurious influence of light, diminishing the amount of combustion, or, in other words, acting as a regulator of respiration. He then proceeds to investigate what are the substances which become oxidized in the process of respiration. In every cell, without exception, that contains chlorophyll, Pringsheim finds a substance that can be extracted by immersion in dilute hydrochloric acid for from twelve to twenty-four hours, to which he gives the name hypochlorin or hypochromyl, and which he believes to be the primary product of the assimilation of the chlorophyll. It occurs in the form of minute viscid drops or masses of a semifluid consistency, which gradually change into long red-brown imperfectly crystalline needles. It is soluble in alcohol, ether, turpentine and benzol, but insoluble in water and in a solution of sodium chloride. It becomes gradually oxidized on exposure to an imperfectly crystalline resinous substance. It is probably an ethereal oil, and an invariable accompaniment of the coloring substance of chlorophyll, and even more universally distributed than starch or oil. It has not yet been detected in those plants which do not contain true green chlorophyll, such as the Phycochromaceæ, Diatomaceæ, Fucaceæ and Florideæ. Starch and oil appear to be reserve substances produced by the oxidation of the hypochlorin caused by light, it being the most readily oxidizable constituent of the cell, more so even than chlorophyll itself. That the hypochlorin-present in variable quantity in every chlorophyll grain under normal circumstances-is subject to continual increase and decrease, may be proved without difficulty. All comparative observations on chlorophyll grains in younger and in older conditions, point unmistakably to the conclusion that the collection and increase of the starch enclosed in the ground substance of the chlorophyll, goes on pari passu with a decrease of the hypochlorin. In dark, the hypochlorin, which does not take any direct part in the transport of food materials, is more permanent than starch; and this fact again is in agreement with the conclusion that its transformation in the cell into more highly oxidized bodies is hindered by the increased respiration in light. In the facts here detailed, and the conclusions derived from them, Dr. Pringsheim believes that an entirely new light is thrown on the cause of the well-known fact that assimilation takes place only in those cells of the plant which contain chlorophyll. This substance acts universally as a moderator of respiration by its absorptive influence on light, and hence allows the opposite phenomena of respiration and elimination of carbon dioxide to go on in those cells which contain it. A more detailed account of the experiments and results is promised by the author in a future paper.-Alfred W. Bennett. ZOOLOGY.1 BUNDLES OF SNAKES.-The statements made by Humboldt as to the piles of snakes he saw in Guiana, can be verified here in our northern woods and swamps. I personally had the pleasure of observing it twice, both times very early in spring, and in locations which could be called wildernesses. I first saw such a bundle of snakes in the neighborhood of Ilchester, Howard Co., Md., on the stony bank of the Patapsco river, heaped together on a rock and between big stones. It was a very warm and sunny location, where a human being would scarcely disturb them. I reasoned that the warmth and silence of that secluded place 1 The departments of Ornithology and Mammalogy are conducted by Dr. ELLIOTT COUES, U. S. A. brought them together. Some hundreds of them could be counted, and all of them I found in a lively state of humor, hissing at me with threatening glances, with combined forces and with such a persistency that stones thrown upon them could not stop them nor alter the position of a single animal. They would make the proper movements and the stone would roll off. All the snakes in this lump were common snakes (Eutania sirtalis L.). The second time I noticed a ball of black snakes (Bascanion constrictor L.) rolling slowly down a steep and stony hillside on the bank of the same river, but about two miles above Union Factory, Baltimore county, Md. Some of the snakes were of considerable length and thickness, and, as I noticed clearly, kept together by procreative impulses. It is surely not agreeable to go near enough to such a wandering, living and hissing hundred-headed ball to examine the doings and actions, and search for the inner causes of such a snake association. As, furthermore, the localities for such mass-meetings of snakes are becoming rarer every year, and our rapidly increasing cultivation of the country must make it hotter for snakes everywhere, only a few naturalists could see such a sight, even if they should look for it in proper time, which, as stated above, seems to be the first warm days in spring.-E. L., Ellicott Mills, Md. REVERSED MELANTHONES.-It is a not uncommon circumstance for collectors, in taking any considerable number of the various so-called species of Melantho, to find a few of them heterostrophal, or sinistral. Dr. Kirtland, in the Ohio Report (quoted by Binney in Land and Fresh-water Shells of North America, p. 44), described one of these abnormal forms as Paludina heterostropha, though he evidently was not altogether clear as to its specific value, for he remarks, "I formerly considered it as a mere variety of P. decisa Say." This same shell Mr. Binney has referred to Melantho ponderosus Say. That all of these sinistral shells are abnormal forms of one or more of the well-known Melanthones is now conceded by most naturalists. It was with not a little surprise, therefore, that the writer recently received from a collector in Illinois a reversed shell of M. subsolidus Anth. labeled with the old and almost forgotten name given by Dr. Kirtland. Having collected a very large number of the three species common in New York, viz., M. rufus Hald., M. integer De Kay, and M. decisus Say. I wish to place on record the following observations made in the spring of 1877, with reference to the relative abundance of these reversed forms. The method pursued was as follows: From impregnated shells, about the time of parturition, the young Melanthones were taken and separated into lots of one hundred specimens each. Every shell was then carefully inspected, and it was found in the case of M. integer that two per cent. of every one hundred shells were sinistral. Of M. rufus, about one and one-half per cent. of every one thousand were thus reversed, while thè per cent. of M. decisus was between two and two and one-half in each hundred. Comparing these averages with the number of mature reversed specimens collected through quite a long period of time, it was found that only about one-tenth of one per cent. survived the accidents consequent on station and environments. How to account for the presence of sinistral shells at all now became the problem. I submit the following suggestions: Many adult and impregnated specimens were dissected and carefully studied, with the result that the position of the embryonic shells was such as to necessarily crowd them one on another. As they increased in size (this is based upon the inspection of shells in different stages of development), their proximity influenced their assumption of form, more and more, and many curious and abnormal shapes were given the growing shells. Binney (l. c., p. 49) figures some of these forms, while others have been described as species (e. g. Paludina (Melantho) genicula Con.). Mr. Binney very properly groups these aberrant forms under M. decisus or M. integer. These "shouldered" and otherwise deformed shells are due to the crowding mentioned above. Is it not possible that the reversed forms originate in a similar way; the embryonic shell increasing in the direction of the least, or no resistance ? The direction of the "whirl" thus started, would be followed in all the succeeding stages of development. Mr. Binney doubts the specific identity of M. rufus Hald., but if the usually accepted definition of " species" be allowed, without good reason. The three above-mentioned forms are associated in the Erie Canal, at Mohawk, N. Y., and so far as species go they are all valid. The latest understanding of a species would, however, relegate them all, together with the other southern and western forms of the genus, to varieties of one sole type.-R. Ellsworth Call, School of Science, Dexter, Iowa. LAWS OF HISTOLOGICAL DIFFERENTIATION.-In a recently published article (Proc. Boston Soc. Nat. Hist., Vol. xx, p. 202) Dr. C. S. Minot discusses certain laws of histological differentiation. He maintains that, first, the most primitive form of tissue is an epithelium composed of a single row of polyhedral cells of equal height. Second, very early in the course of development the ectodermic cells become smaller and multiply faster than the cells of the entoderm. Third, the two horizontal axes of an epithelial cell (or those parallel to the surface of the epithelium) usually remain approximately equal to one another in length, while the perpendicular axis varies independently and to a much greater extent. Fourth, epitheliums increase their surface by the formation of depressions (invaginations) or of projecting folds (evaginations). Fifth, structural modifications of epitheliums usually affect similarly a whole cluster or tract of cells, but rarely isolated cells only. Sixth, probably the primitive cells of the mesoderm are amoeboid in character. For all mesodermic cells, not mechanically united with other cells, but capable of independent locomotion by amoeboid movements, is proposed the collective name of "mesamaboids." The author concludes by saying that if these views are confirmed "we shall then have discovered primary histological differences between the three germinal layers in their earliest stages as follows: EPITHELIAL. A. Small cells, mainly protoplasmatic.. AMCEBOID. C. Cells free in the cavity between the two primitive layers, ecto- Ectoderm. ...Mesoderm. ANT BATTLES.-I have within the past few years witnessed several battles between ants, and in some instances, the curious conduct of the captors towards their prisoners which I think is worth mentioning. The most noted battle took place July, 1878, between two colonies of red ants. The victorious army were medium in size and numbered many thousands; those captured were a much larger ant, but not so numerous. The large ants after a desperate resistance were forced out of their fort, four or five small ants holding on to the antennæ and legs of the prisoner. The captives were usually taken a few inches away from the fort and liberated. All the ants returned to the fight except one who would stand facing his captive for a few moments, then taking hold of the antennæ of the prisoner give three or four pulls; after waiting a short time the pulling was repeated with more determination; the big ant not responding, he was savagely jerked, then he would. lean forward, and a drop of sweet issuing from his mouth, the little ant would approach and drink the nectar, then pick up his captive and hurry home. This was repeated many times during the battle. Some of the prisoners gave up their sweets without so much pulling. I think this battle was for no other purpose than to secure the sweets supposed to be in the stomachs of the captives. These ants were kept prisoners just one week, when they were liberated, marched off in a body and never returned. They were probably kept confined until their sweets were exhausted and then allowed to go free.-A. Miller, North Manchester, Indiana. NOTES ON THE GEOGRAPHICAL DISTRIBUTION OF THE CRUSTACEA.-Mr. Miers in his excellent work on the Crustacea of New Zealand,' enumerated several species which were common to that country and America; these are Neptunus sayi, Platyonichus bipustulatus, Grapsus pictus, G. variegatus, Heterograpsus crenulatus, Nautilograpsus minutus, Plagusia chabrus, Leiolophus planis1 Catalogue of the Stalk and Sessile-eyed Crustacea of New Zealand. Colonial Museum and Geological Survey Department, 1876. |