COPULATORY ORGANS OF THE AMNIOTA. 
25 
pigment as that of the clitoris itself, thus indicating the continuity of the living 
membrane with that of the external surface. The canal was also partially filled near 
its end with a grumous substance, but quite different from the coagulated blood that 
filled the corpus cavernosum.” 
Dumeril and Bibron suggested that the animals pumped water through these 
canals into the abdominal cavity, to counteract the effects of too much evaporation 
during the hot season. To this view Anderson assents. But this hypothesis must 
fall, first, because in the very species, which possibly might need such an arrangement, 
viz., the Land Tortoises, the male canals are closed ; and, secondly, because the often 
extremely narrow and frequently papillary external orifice suggests that nothing can 
pass inwards, whilst the reverse is practicable. Moreover, to receive swamp water 
into the abdominal cavity would imply the greatest danger. 
Geoffroy St. Hilaire and Martin gave a better explanation, viz., that any fluid, 
which somehow or other might collect inside the peritoneal cavity, could be drained 
off, and that consequently Tortoises could not suffer from dropsy unless the canals 
were obliterated, but this suggestion was marred by the addition that “ le liquide, 
probablement sereux, que transmettent ces canaux, doit etre porte en grande partie 
dans les corps caverneux, d’oii il semble qu’il puisse refiner dans les veines.” To this 
mistake they were necessarily led, because they thought there existed communication 
of the canals with the cavities of the corpora cavernosa. 
Mayer found, I think, the right solution for those males in which the canals are 
closed at their extremities ; the serous fluid can be pressed into the penial canals and 
thus assist erection. In Tortoises there is often a considerable quantity of serous fluid 
in the peritoneal cavity. I extracted from a perfectly healthy male Testudo grceca , 
immediately after death, 10 cubic cm. of a fluid, which analysis showed to be serous, 
whilst perhaps the same amount of fluid remained in the animal. 20 cubic cm. is 
certainly a great quantity for an animal not larger than the common Land Tortoise. 
However, when the canals are open, like in the female, their function must, like in the 
Crocodiles, be a different one. In this case they can only serve as a sort of safety 
outlet for the fluid when the abdomen is overfilled with eggs, or if, for some unknown 
reason, too much of this precious fluid has been accumulated ; the latter alternative 
applies to the male, unless we allow for the persistence of the canals by inheritance 
from the other sex. This suggestion, although made with great reluctance, is hitherto, 
nevertheless, the only one that can stand anatomical and physiological reasoning. 
If we homologise the peritoneal canals with the abdominal pores of Fishes, they were 
first used as outlets for the sexual products, i.e., they were in the service of the 
generative system. In the same service, although modified, they are in certain male 
Tortoises. In the other cases they possibly drain the body cavity, and would then, if 
they really are remnants of segmental tubes, have returned to their most primitive 
function. 
The Chelonian cloacal arrangement, as described on p. 21, occurs again, with slight 
MDCCCLXXXVII.—B. E 
