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Show 28 THE DESCENT OF 1\IAN. PART L such as seeds, entering the passage and causing inflammation. 36 In the Quadrumana and some other orders of mam-· mals, especially in the Carnivora, there is a passage near the lower end of the humerus, called the supra-condyloid foramen, through which the great nerve of the fore limb· passes, and often the great artery. Now in the humerus of man, as Dr. Struthers :-11 and others have shewn, there is generally a trace of this passage, and it is sometimes· fairly well developed, Leing formed by a depending hook-like process of bone, completed by a band of ligament. vVhen present the great nerve invariably passes through it, and this cl early indicates that it is the homologue and rudiment of the supra-condyloid foramen of the lower animals. Prof. Turner estimates, as. he informs me, that it occurs in aLout one per cent. of recent skeletons; but during ancient times it appears. to have been much more common. Mr. Busk 38 has. collectecl the following evidence on this head: Prof. Broca "noticed the perforation in four and a half pel~ '' cent. of the arm-bones collect ed in the 'Cimetiere du " Sud' at Paris; and in the Grotto of Orrony, the con,, tents of which are referred to the Bronze period, as" many as eight humeri ont of thirty-two were perfo-· " rated; but this extraordinary proportion, he thinks, " might be due to the cavern having been a sort of' 36 1\1. C. 1\fartins ("De l'Uni te Organique," in 'Revue des Deux l\1o~des,' June 15, 18ti2, p. i 6), and Hackel (' Gonerello Morphologic,' B. 11. s. 278), have both rcmarkeu ou the singular fact of this rudiment sometimes causing death. 37 ' 'fhe Lancet,' J an. 24, 18G3, p. 83. Dr. Knox, 'Great Artists au1l Anatomists,' p. 63. See also an important memoir on this process by· ~~· Grube, in the 'Bulletin de l'Acad. Imp. do St. P ctorsbourg,' tom. ~II. 1867, p. 448. 38 "On the Caves of Gibraltar,'' 'Transact. Intcmut. Congress of Prebist. Arch.' Third Session, 1869, p. 5!. .C HAP. J. RUDIMENTS • 29 " 'family vault.' Again, 1\'I. Dupont found 30 per cent. ·" of perforated bones in the caves of the Valley of the ·" Lesse, belonging to the Reindeer period ; '<Yhilst M. " Leguay, in a sort of dolmen at Argenteuil, observed " twenty-five per cent. to be perforated; and M. Pruner" Bey found twenty-six per cent. in the same condition " in bones from Vaureal. Nor should it be left unno" ticed that l\L Pruner-Bey states that this condition is "'' common in Guanche skeletons." The fact that ancient :races, in this and several other cases, more frequently present structures which resemble those of the lower .animals than do the modern races, is interesting. One -chief cause seems to be that ancient races stand somewhat nearer than modern races in the long line of .descent to their remote animal-like progenitors. 'The os coccyx in man, though functionless as a tail, plainly represents this part in other vertebrate animals. At an early embryonic period it is free, and, as we have seen, projects beyond the lower extremities. In certain ·rare and anomalous cases it has been known, according to Isidore Geoffroy St.-Hilaire and others,39 to form a small external rudiment of a tail. The os coccyx is .short, usually including only four vertebrre: and these are iu a rudimental condition, for they consist, with the exception of the basal one, of the centrum alone.40 They .are furnished with some small muscles; one of which, as I am informed by Prof. Turner, has been expressly .described by Theile as a rudimentary repetition of the ·extensor of the tail, which is so largely developed in many mammals. The spinal cord in man extends only as far downwards as the last dorsal or first lumbar vertebra; but a 30 Quatrefages has lately collected the evidence on this subject. .. Revue des Cours Seicntifiqm·s,' 1867-1868, p. 625. 40 Owen, 'On the Natme of Limbs,' 1849, p. 114. |