18971 MICROSCOPICAL JOURNAL. 207 



seeds of grasses and, as in that, order and in Legumino- 

 sse, the cells are filled with aleurone. 



In Cruciferse several rows of thick and poorly defined 

 cells follow the aleurone layer, being especially marked 

 between the caulicle and cotyledons. The cells of the 

 embryo are quite uniform in size. Distributed through 

 the cotyledons and caulicle occur the [)rocambial vessels 

 and the myrosin bodies in which myrosin is formed. 

 This, according to Hpatzier, is for protection and to break 

 up the glucosides. 



Use of Muoilawe. 



The first and most obvious use of mucilage in crucifer- 

 ous seeds is for the purpose of dissemination, especially 

 in all smaller seeds. This can easily be seen in seeds 

 like those of Lepidium and Capsella. And secondly for 

 the rp:tention of water on the surface, but this is of minor 

 importance. 



Brassica. 



The anatomical structure of the seed of the genus 

 Bras>ica has been studied by numerous investigators. 

 We may mention the following : Oudeman, Tschirch, 

 llarz, Flueckiger and Ilanbury, Hoehnel, Hicks and 

 others. 



Brassica nigra, Koch. 



Pods smooth, one half to three fourths inch long, four 

 cornered, erect, attached to a short pedicel and tipped 

 with a short beak about one eighth of an inch long, about 

 nine seeded. Seeds are black or reddish brown, occa- 

 sionally grayish when more or less moistened; minutely 

 reticulated. The seeds of this species are much smaller 

 than in B. Sinapistrum — three fourths of a line in diame- 

 ter. 



The cuticle covers the epidermal cells as a continuous 

 layer; when mounted in alcohol the outer layer is very 

 much compressed and shows very slight stratification ; 



