صور الصفحة
PDF
النشر الإلكتروني

and hesitatingly, but seems capable of universal application. When he divides species or sub-species into varieties we find the name of the more general group retained, and qualified by a second adjective to denote the variety. Thus, t. 18 of the first volume represents Ranunculus peltatus floribundus, and t. 22 Ranunculus Baudotii vulgaris. R. peltatus is for Mr. Syme a subspecies of R. aquatilis, and R. Baudotii a substantive species. If this mode of nomenclature were modified, so that the second name represented that of the species, while the minor divisions into which it is separable are denoted by a third name added to the other two, we should have a system of nomenclature combining the generalisation, which is the most important characteristic of the old system, with the superior accuracy of the new. It will be convenient (as Mr. Syme does) to drop, as cumbrous and unnecessary, the Greek letter now commonly used to denote a variety. The name Ranunculus aquatilis by itself would be understood to represent a composite or aggregate species, while names of three terms, like R. aquatilis circinatus, R. aquatilis normalis, R. aquatilis tripartitus, would denote segregate or sub-species. The second or specific name must necessarily be applied in the widest sense, and as in the great majority of cases, there would be perfect agreement as to its value, our nomenclature would regain that precision which was imparted to it by Linnæus when he remodelled the system in use in his time. Many differences of opinion would remain as to the proper limitation of the sub-species, but the presence of the second term in the name would make these of little practical moment.

Lastly comes the question, whether these minute details are sufficiently important to bring this trinomial system of nomenclature into general use. Though it may probably be true that every species of plants includes within it a greater or less number of races capable of definition, it does not necessarily follow that these races are deserving of study in all cases, and by every one. It is commonly argued that as they exist in nature it is wrong to neglect them. Carried to an extreme the same argument would lead to the conclusion that, because individuals exist in nature, and no two are in all respects alike, it is therefore the duty of systematists to investigate and record the differences between them. Were we to attempt this, of course all generalisation would be lost in the mass of details. In a less degree it is the same with regard to races. As a matter of high scientific interest, towards the solution of the

recondite problem of genetic biology, accurate observations on with the races of animals and plants are invaluable, and in this sense nos observation can be too minute, no description too precise, no character too trifling, provided it exist in nature. For the ordinary student of nature it seems to us that these minute details are unnecessary, because they are doubtful, fluctuating, and uncertain. To put into the hands of beginners an elementary work in which these forms are elevated to the rank of species, without at the same time drawing his attention to their uncertainty, seems to us to convey an erroneous impression of the state of our knowledge. We get a more accurate picture of the British flora, by restricting it to the Linnean types, than we shall possess when it is worked out in all its details, on the principles of M. Jordan.

Original Articles.

XXII.-On SynOSTOSIS OF THE CRANIAL BONES, ESPECIALLY THE

PARIETALS, REGARDED AS A RACE-CHARACTER IN ONE CLASS OF
ANCIENT BRITISH AND IN AFRICAN SKULLS. * By John Thurnam,

M.D.
OBLITERATION of the sutures of the skull and synostosis of the
cranial bones has of late received much attention, more especially
from those distinguished German anatomists, Virchow, Lucæ, and
Welcker; by whose labours the progress of a rational and scientific
craniology has been so much promoted.

I propose to consider this subject in reference especially to one class of ancient British skulls, viz. those from the chambered and other long barrows of the stone period. I may here observe that the general form of these skulls is elongated or dolichocephalous, and that they are strikingly distinguished from the brachycephalous skulls from the circular barrows of the bronze period; not only by their general form, but also, as would appear, by their greater tendency to early and premature obliteration of the sutures. The mere fact of such a distinction in the skulls derived from two classes of ancient British tombs is of sufficient interest to deserve notice; but

• Read at the Meeting of the British Association at Bath, Sept. 1864; and here printed with additions and corrections.

« السابقةمتابعة »