NOTES AND MEMORANDA. 49 



The Fibrillae of Filifera. — Oscar Schmidt has recently given an 

 account * of the curious fibrillas found among the ordinary horny 

 fibres of the sponge Filifera. These bodies occur in the form of fine 

 knobbed fibres, agreeing in chemical and microscopical character 

 with the fibres of Euspongia, except for the fact that a cell-like body 

 is regularly developed in the knob, when the latter separates from the 

 softer axial portion of the fibrilla. Less frequently the formation and 

 subsequent separation of one or two similar bodies occurs in the 

 axial portion itself. Division of the fibrillfe also takes place. 



Kolliker doubted whether the fibrillse might not be parasites ; but 

 this conjecture is erroneous, as also is the former opinion of Oscar 

 Schmidt himself, that they arise from the ordinary coarse fibres of the 

 horny skeleton. The difliculties attending their isolation are so great, 

 that the author has only recently succeeded in accomjjlishing it, thus 

 making out for the first time their true form. He states that the 

 perfect fibres are knobbed at both ends and resemble children's 

 skipping-ropes. Their dimensions are subject to remarkable fluctu- 

 ations, the long diameter of one and the same knob varying from 

 O'OOS to 0*01 mm., and the length of a carefully isolated fibre from 

 1 • 4 to 1*6 mm. 



The Ovule. — M. E. Warming, the Danish naturalist, has pub- 

 lished in Danish the i-esults of his investigations on the ovule. A 

 translation in French appears in the ' Annales des Sciences Natu- 

 relles ' (occupying more than 70 pp.), from which the follow^ing 

 (being the author's '' Conclusion ") is extracted : — 



I. Few organs have been the object of such varied interpretations 

 as the ovule. Some (Schleiden, St. Hilaire, A. Braun, Strasburger, 

 Wigaud, Eichler, &c.) consider it as a bud, of which each integu- 

 ment is an independent leaf, or a disk (Schacht, Endlicher, Unger) ; 

 the others as an organ of a foliar nature, in which the funicle alone 

 (Eossman), or the funicle and the integuments, is an ovular leaflet or 

 a lube of a leaf. From this point opinions diverge. According to 

 some, the nucleus is a part, a tooth of this leaf (Reissek) ; according 

 to others, a new creation. In the latter case it is sometimes regarded 

 as a bud (Caspary, Rossman), sometimes as a metablast, and latterly 

 as the homologue of a sjDorangium (Brongniart, Cramer, Tieghem, 

 Celakovsky). I agree with the latter opinion. There are also some 

 observers who consider that the ovule may have a different significa- 

 tion in one plant and another, relying on its position either on the 

 summit of the axis or on a leaf. I was formerly of the same opinion, 

 but, thanks to the excellent reasoning of M. Celakovsky, I have recog- 

 nized that the morphological signification of an organ does not 

 dejjend absolutely on its position. Considering the jjerfect concord- 

 ance in the structure of all the ovules of the Angiosperms, even those 

 inserted on the most diverse organs, this opinion is inadmissible ; and 

 comj)arative study has done complete justice to it in negativing the 

 idea that the organ which is the sporangium in the Cryptogams, may 

 become a bud in the Phanerogams. 



It has been desired to invoke the law of shifting, according to 

 * ' Zeitbch. f. wiss. Zool.,' vol. xxx. p. 661. 



VOL. II. E 



