ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 647 



cells. Whether the endosperm is temporary or permanent, its cell- 

 walls are always very thin up to the time when the emhryo attains its 

 full dimensions ; then either its resorption commences, or it becomes 

 gradually transformed into a solid permanent tissue. The presence of 

 endosperm in the mature seed must be regarded as a sign of inferior 

 organization. Its presence is not, however, always constant in the 

 same genus, and it cannot be considered a character of primary 

 importance in classification. 



The period of first formation of the endosperm varies considerably. 

 In the MimoseaB, CoesalpinieaB, and those PapilionaceaB where there is 

 no suspensor, or only a rudimentary one, it begins to develope when 

 the embryo consists of only about a dozen cells ; while in those cases 

 where the suspensor is more developed it originates considerably later. 

 The suspensor, having very often a development in inverse proportion 

 to that of the endosperm, or being formed considerably earlier, has 

 undoubtedly in many cases, like the latter, a function of supplying the 

 embryo with nutrition, though in other cases it may serve no other 

 purpose than that of fixing it. 



The author considers that these embryological facts do not yet 

 enable us to assign to the Leguniinosse their genetic position in the 

 series of vegetable organisms. 



Development of the Ovule of Primula.* — According to F. Pax, 

 the ovules of Primula elatior and officinalis are formed in basipetal suc- 

 cession, but leaving the apex of the placenta and the part next the 

 base of the ovary free. Between the ovules are formed, also basi- 

 petally, and after the first appearance of the integuments, emergences 

 of large-celled parenchyma, varying in size with the species, as also 

 does the number of ovules, which is usually larger in the short- 

 styled than in the long-styled form. The ovules are arranged 

 spirally. 



In P. Auricula and elatior the initial cell of the ovule lies beneath 

 the dermatogen, and first divides by an anticlinal wall into two cells, 

 which then divide periclinally, and one or both of the outer segments 

 again anticlinally. The number of rows of cells produced by the 

 periclinal divisions is increased by anticlinal divisions, and the der- 

 matogen-cells are also found to divide anticlinally. When the rudi- 

 mentary ovule begins to be elevated as a protuberance, periclinal walls 

 are also formed on the apical surface of the protuberance in the first, 

 less often in the second layer beneath the dermatogen and anticlinal 

 walls on its lateral faces in the first layer boneath the dermatogen. No 

 differentiation can yet be detected into periblem and plerome ; and the 

 term endoblem is applied by the author to the tissue beneath the 

 dermatogen. The endoblem finally forms a small-celled parenchy- 

 matous tissue. 



The formation of the nucellus is preceded by a radial elongation 

 of the cells of the outermost layer of endoblem, and the ovular protu- 

 berance now becomes cylindrical, with a nearly rectangular longitu- 



* Pax, F., 'Beitrag zur Keimtniss des Ovuluins von Primula elatior Jacq. u. 

 officinalis Jacq.' 41 pp., Bivslau, 1882. See Bot. Centralbl., x. (1882) p. 316. 



