652 



SCIENCE. 



[N. S. Vol. VIII. No. 202. 



culiar that any attempt to establish a gen- 

 eral type of reproduction is fraught with 

 great danger. 



The Comparative iforphology of the Pistils of 

 the Eanunculaeece, Alismacew and Rosacea. 

 Eenst a. Bessey. 



The uni-ovulate pistil in the Eanuncula- 

 cese originates as an open leaf in whose 

 axil grows a mass of cells from the recep- 

 tacle forming one side of the cavity of the 

 pistil whose other sides are formed by the 

 laminse. and by the curved distal portion 

 of the carpel. Into this cavity grows a 

 median ovule from the axillary mass of 

 receptacular cells. Sagittaria and AUsma 

 have practically the same structure, except 

 that the ovule in the latter grows directly 

 from the receptacle instead of from an out- 

 growth of it. Potentilla and Fragaria show 

 a course of development very similar to 

 the foregoing ; an open pistil is formed, but 

 the ovule, instead of growing from the re- 

 ceptacle, grows from the thickened edge of 

 one or the other of the laminae. This simi- 

 larity of development apparently supports 

 that system of classification of the Angio- 

 sperms, in which there are three diverging 

 lines of development having a common ori- 

 gin, one with the Alismacese first, being the 

 Monocotyledonae, the two others forming 

 the Dicotyledonese, one with the Eanun- 

 culacese lowest being the Thalamiflorse and 

 passing up to the Heteromerte and to the 

 Bicarpellatse, the other with the Eosacese 

 lowest being the Calyciflorse and passing 

 up to the Inferge. 



Origin and Homologies of Blepharoplasts. 



Herbert J. Webber. 



The new features emphasized by the 

 author in this paper were as follows : The 

 blepharoplasts in Zamia arise de novo in the 

 cytoplasm of the generative cell, as pre- 

 viously described by him in the case of 

 Ginlcgo. They appear first as minute bodies 

 with a few kinoplasmic filaments centered 



upon them. At this time no differentiation 

 into outer membrane and interior contents 

 can be distinguished. As they increase in 

 size the radiating filaments become more 

 abundant and an outer membrane becomes 

 plainly difierentiated. 



In the bursting of the blepharoplast to 

 form the spiral cilia-bearing band of the 

 spermatozoid the first change, other than 

 increase in size, is distinguishable in an 

 early prophase of the division of the gen- 

 erative cell. The vacuolated contents of 

 the blepharoplast begin gradually to con- 

 tract away from the outer membrane, which 

 meanwhile increases in size. When the 

 division has reached the metaphase the 

 contents have become contracted to a very 

 small body, and the outer membrane, which 

 has become considerably extended, is shown 

 in section to be broken into numerous seg- 

 ments or plates. The disappearance of the 

 central nucleolus-like contents seems to be 

 correlated in some way with the growth of 

 the outer membrane. Appearances suggest 

 that it is utilized as food matter in the 

 growth of the membrane. In the next 

 stage which the writer has studied, an early 

 telephase, the blepharoplast is represented 

 by numerous round or oblong granules 

 grouped in a somewhat irregular spherical 

 mass, which stain the same as the outer 

 membrane of the blepharoplast in the pre- 

 ceding stage. It would seem that the 

 outer membrane of the blepharoplast breaks 

 up into numerous segments which assume 

 a roundish form and become crowded to- 

 gether into a spherical mass through the 

 action of the cytoplasm. 



In a late telephase a slender membrane 

 can be discovered protruding from this 

 mass of granules and bending toward the 

 nucleus. As the development advances, the 

 membrane grows in length and width, and 

 the granules meanwhile gradually arrange 

 themselves along one side and decrease in 

 number. During the further development 



