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Show 1900.] SOFT ANATOMY OF THE MUSK-OX. 161 a part of the winter coat, which extends even on to the interior surface of the praeputium, for in the bull killed 29th August it is absent and the corresponding surface naked. The next praeputial region, about 7 cm. in length, is also thrown into strong longitudinal folds. In the bull killed in July it is beset with fine woolly-looking hairs about 1| or 2 cm. in length. This portion is evidently richly provided with glands, for in the specimen killed at the end of August, at a time when the rutting-season is approaching, this region is quite covered by a hardened secretion. This is a yellowish-looking mass consisting partly of small roundish nodules like hardened drops and emitting a strong odour of musk. The third and most interior portion, which includes the distal end of the penis, is about 6 cm. in length. Its surface is thrown into a still greater number (16-18) of undulating folds. But the surface is smooth, and there is no secretion conspicuous in this part. There seems to be a rather powerful sphincter at the centre of tbe middle praeputial portion, although it is damaged on the preparations. The length of the two penes preserved in the retracted state is, measured along the curves, respectively 55 and 62 cm. The end of the penis (fig. 13) is blunt, and the urethra ends as a truncate tube (u), which on the left side is curved upward close to the tip of the penis. The urethral tube accordingly does not Fig. 13. Penis of the Musk-ox. extend beyond the penis, and the portion which is not fused together with the end of the latter is very short. On my specimens the free margin on the left lateral side is about 9 m m . and on the median side hardly 4 m m . This condition differs widely from that in the Ovine group. But there is still another difference : the apex of the penis of the Sheep is provided with an expansion like a cushion, forming a kind of glans, but in the Musk-ox nothing of that sort can be seen. The shape of the penis of Ovibos is most similar to that of Damaliscus pygargus as figured by Garrod (I. c. p. 11). From the fact that torms so widely different as Giraffa, Moschus, Elaphodus, Addax, Gazella, Lapra, and Ovis have the urethra prolonged to a more or less setiform appendix beyond the tip of the penis, it may be concluded that this is an ancient characteristicJ of the Ruminsnts, and the ancestors 1 It is very difficult to understand such a feature a., a parallelism, and tertium non datur. PROC. ZOOL. Soc-1900, ISo. \l. 11 |
