And yet, perhaps, by this very struggle the mammal was trained to shrewdness and endurance. The primitive mammals laid eggs like reptiles or birds. Only two genera, echidna and platypus, survive to bear witness of these old oviparous groups, and these only in New Zealand. These retain several old reptilian characteristics.
Bracts in the inflorescence of crucifers are ordinarily wanting, but may be seen in some genera, Erucastrum pollichii being perhaps the most widely known instance, although other cases might easily be cited. For our special purpose we may take up only the more simple cases that may be available for experimental work.
If the foregoing discussion upon the nature of these groups is based upon trustworthy principles, we must admit that they are all founded upon distinct categories of characters, the primary divisions, or the Branches, on plan of structure, the Classes upon the manner of its execution, the Orders upon the greater or less complication of a given mode of execution, the Families upon form; and it now remains to be ascertained whether Genera also exist in Nature, and by what kind of characteristics they may be distinguished.
Among the Hymenoptera, few genera have created greater dispute than the anomalous genus Trigonalys of Westwood. Mr. Macgillivray one day brought to the British Museum the nest of a Brazilian Polistes. My friend, Mr.
A case less open to the objection of negative evidence, however, is that afforded by the Tetrabranchiate Cephalopoda, the forms of the shells and of the septal sutures exhibiting a certain increase of complexity in the newer genera.
It is a mistake to suppose that weaver-birds are only found in Africa and the Old World, as stated in the works of many naturalists. In tropical America, birds of this character are found in many species of the genera Cassicus and Icterus, who weave pensile nests of a similar kind upon the trees of the Amazon and Orinoco.
The remains of fishes of the Upper Cretaceous formations consist chiefly of teeth belonging to the shark family. Some of the genera are common to the Tertiary formations, and some are distinct. But we meet with no bones of land-animals, nor any terrestrial or fluviatile shells, nor any plants, except sea-weeds, and here and there a piece of drift-wood.
Taken as a class, windflowers are so beautiful that we cannot grow them too plentifully, and but few other genera will so well repay cultural attention at all seasons. F.W.B., in The Garden. The story of Lieut. Greely's recovery after his rescue from Cape Sabine is given by Passed Assistant Surgeon Edward H. Green, U.S.N, of the relief ship Thetis, in a communication to the Medical Record.
Now and then a pretty feather is intertwined or fastened to the outer sides, the stem being always so placed that the feather stands out beyond the surface." The best evidence, however, of a taste for the beautiful is afforded by the three genera of Australian bower-birds already mentioned.
It is a fact well known to the students of paleontology, that species and genera which have been long on the earth are apt to become in a way rigid as regards their qualities of body and mind.