Paper - The external characters of a second Australian foetus (1938)

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Wood-Jones F. The external characters of a second Australian foetus. (1938) J Anat. 72: 301-104. PMID 17104695

The External Characters of a Second Australian Foetus

By Frederic Wood-Jones Melbourne


In a previous note (J. Anat., Lond., vol. Lxvi1, pt. Iv, p. 549) I described the external features of an Australian foetus of about the 17th-18th week of intrauterine life. The subject of the present note is considerably younger and, both by its general state of development and by its measurements, must be assigned to a period not later than the 9th week. The specimen was procured many years ago by the late Mr Herbert Basedow at Alice Springs and, despite its having had a rather chequered career since the death of Mr Basedow, there is no doubt about its authenticity. The condition of preservation is not perfect, the head having suffered some shrinkage and flattening, but the histological condition of the tissues is surprisingly good.

Measurements

In the table of measurements given below I have included those of a normal white foetus of slightly larger size for comparison with the indices obtained from the Australian foetus.

Table of measurements

Australian

Measurement aboriginal White Rump-vertex 37 41 Suprasternale-symphysion 15 20 Arm 8 9 Forearm 6 8 Hand 5 6 Thigh 8 10 Leg 6 7 To sole of foot -2 +2 Length sole of foot 6 7

The interest in these measurements lies in the fact that, as in the 17th-18th week foetus, the great relative length of the limbs, which characterizes the adult aboriginal, is already well marked at about the 9th week of intrauterine life.

While the upper extremity/lower extremity ratio is very nearly the same in the white and aboriginal foetuses and the arm-forearm/leg-thigh ratio is identical; the upper and lower extremity/trunk length ratios are considerably higher in the aboriginal. The hand and foot of the aboriginal are also considerably longer relative to the trunk length. 302 Frederic Wood-Jones


Fig. 3. External genitalia.


Fig. 2. Hind end of his body showing caudal extremity and external genitalia. Fig. 4. Left pinna. The External Characters of a Second Australian Foetus 303

Table of indices

Australian aboriginal _ White Arm and forearm 93-3 Trunk length 85 Upper extremity Trunk length 1266 115 Thigh and leg Trunk length 93:3 85 Lower extremity ‘Tronk length 103-3 95 Arm and forearm , Leg @nd thigh 100 100 Upper extremity Lower extremity 126 121 Hand ‘Prank length 33:3 30 Foot Trunk length 40 35


Fig. 5. Left hand. Fig. 6. Sole of right foot.

In the general question of the antiquity of human racial differentiation it would seem to be a fact of considerable interest that the typical racial proportions of the Australian aboriginal are fully established at the 9th week, when the two proximal segments of the limbs are only 14 mm. in length.

General Characters

The foetus is 87 mm. in R-V length. The eyes are closed and the edges of the lids are smoothly covered by a growth of epitrichium. The mouth is open: the anterior nares are occupied by epithelial plugs. The vitelline loop is exposed by the tearing of the cord from the body (see Fig. 1). The caudal process is unusually well marked and, although there is only a very short free tail, the prominence of the caudal tubercle is well developed (see Fig. 2). The development of the external genitalia appears to be somewhat precocious. The sex is obviously male. The ostium urogenitale is situated about midway on the body of the penis and persists only as a narrow cleft in front of the closed inner genital folds (see Figs. 2 and 8). The whole genital tubercle appears large when comparison is made with white foetuses of about the same size.

The pinna, on the other hand, would appear to be somewhat rudimentary in development for a 37 mm. foetus with closed eyes. The tuberculum tragicum is well defined and the hyoid derivatives have taken definite shape; but the pinna itself is but little sculptured from the general skin field (see Fig. 4).

On neither fingers or toes is there any sign of developing nails, even in microscopic sections. Upon the palm, the 4th, 8rd and fused Ist and 2nd pads are distinct and on the sole all four pads are separate and well defined. The central digit of both hand and foot is the longest (see Figs. 5 and 6).


Cite this page: Hill, M.A. (2020, August 10) Embryology Paper - The external characters of a second Australian foetus (1938). Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Paper_-_The_external_characters_of_a_second_Australian_foetus_(1938)

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