. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. 312 MARSUPIALIA. but in this circumstance we may perceive an example of the retention of a typical structure at the deeper seated part of a system of organs, when not incompatible with a slight modifi- cation of a peripheral segment of the same system ; it being by no means obviously neces- sary to abrogate the division of the urethral bulb simply because the blood accumulated in each division was to be driven in a concen- trated current upon a single, instead of a dou- ble glans penis. The intermediate structures of the
. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. 312 MARSUPIALIA. but in this circumstance we may perceive an example of the retention of a typical structure at the deeper seated part of a system of organs, when not incompatible with a slight modifi- cation of a peripheral segment of the same system ; it being by no means obviously neces- sary to abrogate the division of the urethral bulb simply because the blood accumulated in each division was to be driven in a concen- trated current upon a single, instead of a dou- ble glans penis. The intermediate structures of the glans be- tween the two extremes above instanced are presented by the Ursine Dasyure, Koala, and Wombat. In the Koala (jig. 135, B) the glans penis terminates in two semicircular lobes, and the urethra is continued by a bifurcated groove along the mesial surface of each lobe. In the Wombatf^'g. 135, C)thereisasimilarexpansion of the urethra into two divergent terminal grooves, but the glans is larger, cylindrical, and par- tially divided into four lobes :* the chief struc- ture of interest in this part of the Wombat is the callous external membrane of the glans, and its armature of small recurved, scattered horny spines, which do not occur in any other Marsupial animal. The small retroverted pa- pillae on the infundibuliform glans of the Koala and on the bifurcate glans of the Phalan- gers and Petaurists are not horny. In the Perameles lagotis not only is the glans bifurcate, but each division is perforated, and the urethral canal is divided by a vertical septum for about half an inch before it reaches the forked glans. From the septum to the bladder the canal is simple, as in other Marsupials. The bifurcations of the glans in the Opossums and Phalangers are simply grooved. If the experiments of Haighton and the detection, by Drs. Bischoffand Barry, of sper- matozoa upon the ovary itself after coitus, had not rendered the question of the neces- sity of the contact of the seme
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