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TRANSLATIONS. 



Leickart on the Mickopyle and Minute Stricture of the 

 Egg-shell in Insects. (Miiller's Archlv., 1855, p. 244.) 



The Author, from observations made upon tlie ova of 180 

 insects belonginj^ to the most various g^roups, is induced to 

 come to the following conclusions. As regards more espe- 

 cially the existence of a micropyle, he conceives that no 

 doubt can be entertained with respect to the following 

 points : 



1. Tl)at this apparatus is characteristic of all insect 

 ova ; 



2. That it consists sometimes of a simple, sometimes 

 of a compound orifice, which passes through the tunics of 

 the ovuniy and serves 



3. For the admission of the spermatic filaments. 



The last-noticed fact, it is true, has been demonstrated in 

 but a small number of species — not more than about a dozen 

 — but it may, nevertheless, perhaps be regarded as quite as 

 certain as tlie others. For the doctrine of impregnation, 

 however, this latter proof is of the highest importance, as by 

 it alone has the question respecting the micropyle of animal 

 ova received its physiological solution. Hitherto it might 

 always be doubted — as in fact it always has been — whether 

 the openings and canals which were some time since dis- 

 covered to exist in the envelopes of the ovarian ova in various 

 animals, and compared, as regards their external conditions, 

 with the micropyle of the vegetable ovum, also really pos- 

 sessed the physiological import of that micropyle. 'J he 

 researches and statements of Keber cannot be regarded as 

 having solved this question, since the spermatic corpuscle, 

 whose penetration and metamorphoses were so laboriously 

 described by that observer, is, as is wc^ll known, anything but 

 a spermatic corpuscle at all, being only a thickening of the 

 vitelline membrane at tlie base of the micro])yle process, and 

 to be found unaltered even after the escape of the eiiibrycs 

 (vide Bischoff, ' Widerlegung,' and Hessling, ' Zeitsch. fur 

 wissenschaft. Zool.' vol. v. p. 392). Tlie preceding observa- 

 tions, therefore (by Leuckart, in Miill. ' Archiv.' 1855). to- 

 gether with those of Meissner, of which they are quite inde- 

 pendent, are tlie first, and, up to the present time, the only 

 cmes demonstrating the penetration of the spermatic filament^ 



