ZOOLOGY AND BOTANY, MICROSCOPY, ETC. G21 



ngroc ill the main with those of Flcmming with regard to the development of 

 the spermatozoids in Snlcmiandra. Jie regards the "head" of the sperma- 

 tozoid of animals as strictly homologous to the " body " of that of })lants. 



Since the latest division of the mother-cells of all spermatozoids takes 

 place nearly or quite simultaneously, the further development of the 

 spermatozoids advances with uniform rapidity, so that all those in an 

 anther id iuni arc rijso at the same time. The walls of the mother-cells 

 remain until the spermatozoids are nearly mature ; then they are partially 

 absorbed, and the sejiarate cells become isolated, and at first still inclosed 

 in a thin pellicle. Notwithstanding the small size of the nucleus, it is 

 certain that it consists of an ordinary framework with relatively large 

 microsomes. 



The differentiation of the young spermatozoid begins with a contraction 

 of the substance of the nucleus. On one side is found a more or less distinct 

 fissure or constriction, so that the nucleus has a sickle-shaped appearance 

 from above. The contracted framework of the nucleus has now the form 

 of a thick curved band, the ends of which approximate, and the margins 

 are bent inwards. As development proceeds this band becomes thinner 

 and flatter, until it assumes its final form of a coiled thread. The change 

 of form is accompanied by a corresponding internal differentiation. The 

 reticulate structure gradually disappears, and the strongly refractive body 

 of the spermatozoid becomes finally nearly homogeneous. If it is now- 

 stained with ha3matoxylin or saffranin, it is easily seen that the microsomes 

 are still separated, while in the mature spermatozoid the whole of the band 

 takes a uniform intense colouring. 



The body of the spermatozoid is therefore formed out of the nucleus of 

 the mother-cell. Their behaviour towards reagents shows that the cilia 

 originate from its cytoidasm. They are formed only during the latest stage 

 of development of the spermatozoid. The development of the vesicle, which 

 is always present, advances J;rt}•^J;ass^t with that of the sj^ermatozoid. It 

 results from the constriction which accomjianies the first contraction of the 

 nucleus, and increases in proportion as the nucleus contracts. The curved 

 ends of the growing spermatozoid completely inclose it. It has an outer 

 extremely thin wall, which is difficult to detect. It is clear that the vesicle 

 is derived from the cytoplasm, which accounts for the presence in it of 

 starch. 



The fixing materials used in these observations were alcohol, a concen- 

 trated aqueous solution of corrosive sublimate, a 1 per cent, solution of 

 chromic acid, and a concentrated aqueous solution of picric acid. The most 

 convenient staining material, after fixing with alcohol or corrosive sublimate, 

 is a very dilute aqueous solution of hasmatoxylin. Gold chloride often 

 gave striking results after treatment with chromic or picric acid. Saffranin 

 was also useful in some cases. 



Cryptogamia Vascularia. 



Prothallium and Germ-plants of Lycopodium inundatum.* — Further 

 examination by Prof. K. Goebel of the prothallium oi Lycopodium inundatum 

 confirms previous observations. It agrees with the type of L. cernuum 

 rather than with that of L. annotinum and Phlegmaria, growing erect, and 

 containing chlorophyll in the portion above the surface. The cells are 

 attacked by the hyphse of a fungus, probably a Pythium, in the same way 

 as the prothallium of L. cernuum. Antheridia and archegonia occur in 

 close contiguity on the same prothallium. The young plant has a single 



* Bot. Ztg., xlv. (1887) pp. 161-8, 177-90 (1 pi.). Cf. this Journal, 1886, p. 828. 



