THE POPULAR SCIENCE MONTHLY.
for it are, that it gives by contact indications of the volume of heat escaping by radiation, and the velocity of loss; also, that by blowing on the bulb the degree of combustion that takes place in the lungs is shown. It is likewise serviceable as a means of detecting the exact position of deep-seated local trouble, giving valuable indications where the thermometer fails.
A New Fossil Crustacean.—A new crustacean species, allied to Eurypterus and Pterogotus, has been described by A. R. Grote and W. H. Pitt, under the name of Eusarcus scorpionis. The specimen was found in the water-lime group at Buffalo, N. Y. Its length is 250 millimetres, and its greatest width 110 millimetres. The cephalo-thoracic portion appears to be separate from the body; the legs are in the same number as in Eurypterus; the swimming-feet appear to differ by the straighter, less rounded outer margins; the spines of the anterior feet appear to be long, curved, and to have an anterior direction. The absence of chelate appendages to the posterior margin of the feet is particularly noticeable. The first seven broad segments of the abdomen form a large ellipse. There is an evident and remarkable narrowing of the succeeding caudal segments. The interest which attaches to this remarkable crustacean arises from the discovery of a form which may be allowed to be higher than Eurypterus and Pterogotus.
Reptilian Affinities of Birds.—Prof. E. S. Morse has for a long time made a study of the bones of embryo birds. At this year's meeting of the American Association he recalled briefly the evidence he had shown last year regarding the existence of the intermedium in birds, by citing the embryo tern, in which he had distinctly found it. This year he had made a visit to Grand Menan, expressly to study the embryology of the lower birds, and was fortunate in finding the occurrence of this bone in the petrel, sea-pigeon, and eider-duck. This additional evidence showed beyond question the existence of four tarsal bones in birds as well as four carpal ones. In these investigations he had also discovered embryo claws on two of the fingers of the wing—the index and middle finger. Heretofore in the adult bird a single claw only had occurred in a few species, such as the Syrian blackbird, spur-winged goose, knob-winged dove, jacana, mound-bird, and a few others; and in these cases it occurred either on the index or middle finger, or on the radial side of the metacarpus. All these facts lent additional proofs of the reptilian affinities of birds.
American Pedigree of the Camel.—Though the evolutional pedigree of the horse may be distinctly traced in the succession of equine genera whose remains are found in the Tertiary strata of our Western Territories, nevertheless, the horse, as he at present exists, is not indigenous to this continent, but has been imported from Europe. The pedigree of the camel may also be constructed from materials supplied by American paleontology. Prof. Cope has recently unearthed a number of genera which must be regarded as the ancestors of the camel. And it is worthy of note that, although the more prominent genera of the series which resulted in the horse, for instance Anchitherium and Hippotherium, have been found in European formations, no well-determined form of the ancestral series of the camel has up to the present time been found in any formation of the Palæarctic region. "Until such are discovered," says Prof. Cope, "there will be much ground for supposing that the camels of the Old World were derived from American ancestors."
Arctic Meteorology.—During Weyprecht and Payer's expedition to the north-polar regions the air in winter seemed always to contain particles of ice. This was seen not only by parhelia and paraselenæ when the sky was clear, but also in astronomical observations. The images of celestial objects were hardly ever as clear and well defined as at lower latitudes, although the actual moisture in the atmosphere was far less than is usual in temperate climes. It happened very often that, with a perfectly clear sky, needles of ice were deposited in great quantities upon all objects. It was impossible to determine the quantity of atmospheric deposits, as during the snow-storms no distinction could be made between the