1903. ] TRANSPOSITION OF MAMMALIAN TESTES. 331 
and the oviduct usually possessing no anatomical connection. 
How important this is may not only be inferred from @ priori 
considerations, but also from the discovery of the many structural 
devices adapted to this end. Thus there occurs the “ develop- 
ment of special folds of the peritoneum, which practically ensure 
the passage of the ova into the oviduct when they are extruded 
from the ovaries. The oviduct, moreover, has a large and 
fimbriated mouth, called in human anatomy the ‘morsus diaboli.’ 
This almost wraps round the ovary, and thus prevents the ova 
from straying in the wrong direction. Moreover, the ovary itself 
is often so arranged that it can easily be withdrawn into a pocket 
of the peritoneum, from which the obvious exit is by the gaping 
mouth of the oviduct. This disposition of the generative parts is 
still further modified in a few animals, such as the Rat and the 
Kinkajou. In these animals the mouth of the oviduct actually 
opens into the interior of a closed chamber which contains the 
ovary” (Beddard). Thus there exists ample reason for the 
retentive ligaments usually associated with the mammalian ovary 
(see Appendix). 
The Genitalia and Conditions of Locomotion in Ichthyopsida 
and Sauropsida. 
If, as we have observed, the conditions of mammalian loco- 
motion alone subject the organisation to those concussive influences 
which have effected, among other changes, the transposition of 
the testes; and if, as we have also seen, only the highest mani- 
festations of terrestrial activity are capable of producing complete 
testicular descent, then we may be certain that neither in the 
relatively inactive terrestrial Reptilia, the active aerial Aves, nor 
the aquatic Pisces will a ike phenomenon occur. In Reptilia, 
though Ophidia and many Lacertilia are capable of brief spasms 
of great activity, the total impulsiveness is very small and of low 
degree. This is not only due to general passivity, but also to the 
fact that “the body of a reptile is, as it were, slung between its 
limbs like the body of an eighteenth century Ghanigt between its 
four wheels,” with resulting i imperfection of the ‘relations of the 
limbs to the trunk from the point of view of a terrestrial 
creature” (Leddard). Apart from the absence of the causal 
conditions, the depression of the trunk and consequent liability 
of injury to the testes would in itself have negatived descent 
(cf. Phocidee above). 
In the Anura, the only terrestrial amphibia which concern us, 
adoption of terrestrial habits, resulting in a higher degree of 
impulsiveness, has as usual for its concomitants structural con- 
centration and increased retentivity or transposition. Here the 
testes have assumed a “full oval form, compact and undivided : 
they are situated, as shown in the Frog, on the ventral side of 
the anterior half of the kidneys” (Owen). That the testes 
have slightly descended in correspondence with the saltatory 
