848 MR. GULLIVER ON THE ANATOMY [ Dec. 6, 
saw that those females which were distended with eggs had a similar 
genital papilla, only shorter and with a wider canal than in the male. 
Through this vulva the eggs, each about a fortieth of an inch in dia- 
meter, readily escaped in single file. The intimate structure of the 
organ is the same, and the tube a genito-urinal outlet, in both sexes. 
From the above descriptions, it appears that during the spawning- 
season, the peritoneum of the Lamprey is not in either sex a shut 
sac, for it opens outward by the tubular canal, through and along 
the centre of the genital papillee of the male and female—and that 
in each sex the genital outlet is single, with its external opening in- 
dependent of and separate from the so-called cloaca. 
Spermatic Filaments, fig. 6.—These were extremely abundant. 
3 . 1 . : 1 : 
Their mean length is ooo) and their thickness Len of an inch. 
Though but little acted on by acetic acid, they do not preserve their 
shape well in drying. 
Indeed the effect of this acid seems to indicate different chemical 
characters of the spermatozoa of different animals. While it has no 
effect on those filaments of most mammalia, it dissolves or destroys 
very quickly the spiral spermatozoa of birds; and yet the club- 
shaped spermatozoa of this class resist its action like those of mam- 
malia, as more particularly noticed in the ‘ Proceedings’ of this 
Society, July 26, 1842. 





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In the above woodcut, figs. 4 and 5 show the genital papillee of 
the natural size—tig. 4 of the male, and fig. 5 of the female; in each 
