DE. W. H. EANSOM ON THE OVUM OF OSSEOUS EISHES. 
501 
K. E. Von Baer (Untersuchungen fiber die Entwickelungsgeschichte der Fische, 
1835) saw in the egg of Cyjyrinus Blicca (white Bream) a clear circle in the centre of 
the germ (discus proligerus), which when viewed full face had a dark halo around it 
and resembled an area pellucida, but when seen in profile was recognized as a funnel- 
shaped depression in the outer membrane. He says further, “ I can only conceive the 
formation of this funnel taking place by the passage outwards of the germinal vesicle, 
through the centre of the germ, as I have seen occur in the egg of the frog.” 
It may be said therefore that Baer observed the funnel of the micropyle, and correctly 
described its position relative to the parts of the egg, but did not see the aperture 
through the yelk-sac or properly interpret the structure. 
M. Doy^re communicated a paper to the Soc. Philomathique de Paris, Dec. 15th, 
1849 (see l’lnstitut, vol. xviii. p. 12, 1850), in which he described the micropyle in Syn- 
gnathus Opliidium , clearly indicated its relation to the discus proligerus, measured the 
aperture, and without doubt appreciated its significance in the act of impregnation, 
without, however, affording any experimental evidence of its uses. 
My paper, read November 23, 1854, and published in the Proceedings of the Royal 
Society, was next in order of time. 
C. Bruch (Zeitschrift fur Wissensch. Zool. B. vii. 1855) announced his discovery of 
the micropyle in the eggs of trout and salmon in a letter to Professor Siebold, December 
28, 1854. He did not make out its relation to the proligerous disk, and failed in his 
attempts to prove that it served for the entrance of spermatozooids. He, however, rightly 
interpreted the structure, and claimed to have first established on a firm basis the exist- 
ence of a micropyle in vertebrata. 
My observations on the eggs of trout and salmon were made in the same season, De- 
cember 1854 and January 1855, and the results were communicated in the latter montli 
to Dr. Allah Thompson (Cyclopaedia of Anatomy and Physiology, vol. v. p. 104). 
Reichert (Muller’s Archiv fur Anat. Physiologie, &c. 1856, p. 83) described the 
micropyle in the egg of the pike and of several other fishes, failing, however, to find it 
in perch. His first observation was made immediately before Professor Bruch’s paper 
came to his hand. He did not describe the relation of the micropyle to the other parts 
of the egg, or give any proofs that it served to give entrance to the spermatozooids. 
The credit of priority rests mainly with Doyere. His observation was unnoticed for 
some time, and my experiments were made and published without any knowledge of his 
discovery or of the earlier one by Von Baer. 
Bruch worked on this subject also without a knowledge of what had been done 
before, and Reichert with only a partial knowledge. 
February 23, 1867. 
