About two years ago, while examining the interesting series of prehistoric skulls in the collection of the Davenport Academy of Sciences, the writer became involved in an attempt to account for the supernumerary bone which someone has marked the “inca” bone. What the significance of the name may be, I do not know, but the significance of the fact is the object of the inquiry involved in this paper

Nutting, C. C.

English

University of Northern Iowa

Proceedings of the Iowa Academy of Science Volume 1 Part 4, 1893; (1887) - Article 40 1893 The Homology of the Inca Bone C. C. Nutting Copyright ©1893 Iowa Academy of Science, Inc. Follow this and additional works at: https://scholarworks.uni.edu/pias Recommended Citation Nutting, C. C. (1893) "The Homology of the Inca Bone," Proceedings of the Iowa Academy of Science, 1(Pt. 4), 119-120. Available at: https://scholarworks.uni.edu/pias/vol1/iss4/40 This Research is brought to you for free and open access by the Iowa Academy of Science at UNI ScholarWorks. It has been accepted for inclusion in Proceedings of the Iowa Academy of Science by an authorized editor of UNI ScholarWorks. For more information, please contact scholarworks@uni.edu. IOWA AGADEl\lY OF SCIENCES. 119 THE HOMOLOGY OF THE "INCA" BO.NE. BY C. C. NUTTING. Ahout two years ago, while exarnmmg the interesting series of prehis-toric skulls in the collection of the Davenport Academy of Sciences, the writer became involved in an attempt to account for the supernumerary bone which some one has marked the• 'inca" bone. \Vhat the significance of the name may be, I do not know, but the significance of the fact is the object of the inquiry involved in this paper. In a series of about twenty skulls examined by me there were at least six which exhibited the so-called "inca" bone, ·.vhich is a portion of the occipital, separated from the remainder by a very distinct suture extending across the hone, following the "superior curved line," and ahout one-half inch above it. This suture is quite constant in position in every skull show-ing the "inca" bone. The portion of the occipital which is thus cut off shows a tendency to itself divide into two or three pieces. But the sutures in this case are not constant in position and may, in fact, occur in almost any portion of the "inca" bone. In attempting- to homologize this peculiar bone, three possibilities occur: First-The inca bone is the homologue of the supraoccipital of certain of the lower mammalia. Second-The inca bone may be simply an enormously developed wormian bone. Third-It may be a persistent embryonic character. As to the first hypothesis, i. e., that it is the supra occipital, we find that the supraoccipital in lower mammalia reaches to and forms part of the borders of the foramen magnum. The "inca" bone, on the contrary, is always remote from the foramen magnum, being above the superior curved line. It can thus be seen that the bone in question cannot be the supra occipital. The second hypothesis, i. e., that we have here merely an enormously developed wormian bone, would, at first thought, seem to be unworthy of serious consideration. But Gray' says, in his classic Anatomy: "They (the wormian bones) vary much in size, being in some cases not larger than a pin's head, and confined to the outer t:ible; in other cases so large that one pair of these bones may form the whole of the occipital bone ahove the superior curved lines." This is the extent of the ''inca" bone in all cases, and in at least one !Gray's Anatomy, Eleventh Edition, p, 181. 1Nutting: The Homology of the Inca BonePublished by UNI ScholarWorks, 1893120 IOWA ACADEMY OF SCIENCES. skull, No. 9 in the sketches, the inca bona is vertically divided into two by a suture a little to the right of the median line. It is probable that if this particular skull were placed in the hands of Dr. Gray he wonld consider the "inca" bone enormously developed wormian bones. lt seems to me, how-ever, that there is a more natural explanation and one more in accord with the facts. I have here the tabular portion of the occipital cf a well ad rnnced human fffitus. It is what would correspond to the supraoccipital of some of the lower mammalia. The bone is cleft on each side, the fissure being just above what will ultimately be the superior curved line. Looking on the inside of the bone, there are indications that at a still earlier stage of development this bone was separated into two parts, the separation being along a line a little abo1'e the superior curved line. This is exactly the condition of affairs fonnd in the skulls with the "inca" bone. In other words, we have in the ordinary human embryo a condition of affairs which we find in the adult skulls of these prehistoric people. It seems likely, therefore, that we have here a persistent embryonic character. Unfortunately I was unable to find any satisfactory record of these skulls in the catalogue of the Academy. Most of them were simply entered by number. One was marked "De Kalb Co., 111.," and I was told that it and several others came from prehiotoric gra1·es in that locality. If the "inca bone" was a characteristic of a definite race of human beings, it would certainly be sufficient to constitute a new species of the Genus Homo. If it was only au occasional, or even somewhat frequent abnorm-ality, it may be regarded simply as a "reversion" indicating that the race possessing it was of a peculiarly low type. NOTES ON THE DISfRIBUTlON OF HEi\lIPTERA. BY HERBERT OSBORN. During the past few years I have received from a number of different sources, partly by purchase and partly by sets sent me for determination, a number of collections of Hemiptera, and as some of these records exteud the known distribution of the species, or give more specific data regarding them, it seems desirable to give them a permanent record. The principal collections on which the paper is based, aside from my own, are those made by Mr. Wickham in New Mexico, Arizona and Cali-fornia, and in the northwest, and purchased by the Agricultural College or by myself, those from Prof. C. P. Gillette, of Colorado, Prof. Lawrence Bruner in Nebraska, Prof. V. L. Kellogg in Kansas, Dr. C. i\1. "'eed in New Hampshire, and others. The Hemiptera present us with a number of interesting cases of distri-bution. ln some cases apparently dependent upon food plant, in others 2Proceedings of the Iowa Academy of Science, Vol. 1 [1893], No. 4, Art. 40https://scholarworks.uni.edu/pias/vol1/iss4/40

The Homology of the Inca Bone

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The Homology of the Inca Bone

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