Trochosphsera sequatorialis. By Herr Semper. 243 
the intestines are contracted, the sphincter immediately closes, com- 
pletely separating it from the cloaca. 
Though I have never observed an opening of the anus after a 
contraction of the bladder, hut, on the other hand, have noticed the 
contractions and expansions as described above in the case of many 
specimens, and in the same individual specimen for a long time, 
yet I will not assert that the contents of the bladder are not at 
times transmitted to the anus. Still, from what has been said 
above, I think it certain that it is far oftener driven back into the 
stomach instead of being emptied away. If then the liquid from 
the excretory organ really gets into this bladder — as is probable 
— it would follow that it cannot be considered pure excrement ; 
it must, on the other hand, be regarded as in a certain way necessary 
or serviceable a second time for the nourishment of the creature, 
since in the manner described it is again driven back into the 
resorbent apparatus. The so-called excretory organ then is not 
what its name implies, at any rate not entirely such ; and thus this 
organ — physiologically regarded — would be intimately connected 
with the kidneys of the molluscs, i. e. of those living in water, in 
the case of which this organ undoubtedly serves for passing water 
into the blood. The excretory organ is double, as usual, and 
exhibits the well-known formation of this organ in Rotatoria. At 
the cloaca begin the two ducts (1 k) in such a manner as to be 
situated pretty nearly in the meridian plane passing through the 
two eyes ; they then bend forwards towards the mouth, and at the 
same time towards the equator, and pass under the muscle-band at 
the side into the glandular part. The duct has a coat of con- 
siderable thickness (7 a) ; beneath the muscle it divides off, and 
quickly swells to the two irregularly formed glandular flaps (7 b, b ) 
in which the upper part of the canal winds. Each glandular flap 
passes into the two ciliated channels (7 c), which exhibit four or 
five of the characteristic ciliated tags rising upon them (7 g). At 
cl the two channels c cross ; here one of the two must end or they 
become joined ; for from this place only a single channel c can be 
traced up to the before-mentioned nerve 5 ; by this it is held fast. 
In this last section a single ciliated tag occurs. 
Of the sexual organs I only recognized the female. They are 
exceedingly simple ; from a single ovary a thin oviduct takes its 
rise (1 A and i). The ovary (1 h, 9) is a flat band, rather broad, 
which is situated close above the equator in the two back quadrants 
away from the mouth (2 h) ; with its flat surface it places itself 
along the skin through almost its whole length, only the free end 
bends away a little (2/i), as also does the end from which the 
oviduct originates (2 i). The whole band of the ovary is filled 
in its undeveloped state with small granular cells, three or four of 
