MET HOW 23 



dcfin sion being . but little displacement of the 



walls, so that up to the h>t !:-,.-.- of the spernvceUs 

 ns can be plainly traced, and the ftpermato- 

 narking the early divisions. While . 



these i cells < usuall) ame stage of mitosis, 



segment of the antheridium may show a different stage of nuclear 

 This was also noted by Humph re tudy of Fouombromia 



Ion gist t a [ i j . 



Spermatogenesis 



Pallavici*ia ZoUingeri proved the best species for a study of Sperma- 

 togenesis, and the investigation of i ect was mainly devoted to that 

 v In the earliest stages procurable the final mitosis had taken 

 place, and the two n < i had begun to assume the elongated 

 form found in the compl. matozoid (Fig. 12, A. B). The final 

 accompanied by the formation of a delicate but perfectly evi- 

 dent division wall separating the pair of spermatocytes. The spermato- 

 at this stage closely resemble those of Calycularia radtftthsa (Camp- 

 bell [ The length of the young spermatocyte in P. Zollim- 



:s about ows the pair of spermatocytes at this 



stage. The blepharop now has the form of a somewhat curved 



rod at the end of the elongated nucleus. Sometimes the blepharoplasts 

 of the pair of spermatocytes are at the same end. sometimes at opposite 

 ends. With the development of the spermatozoid. the blcpharoplast. as 



. elongates rapidly, and becomes a slender curved rod. hooked at 

 the free apex, and following the curve of the elongating nucleus which 

 becomes crescent-shaped, with the anterior end more or less conspicuously 

 attenuated (Fig. 12, D-K}. In some of the preparations there was pres- 

 ent between the blepharoplast and the anterior part of the sperm-nucleus 

 a thick, rod-shaped body, which perhaps represctr N'ebenkorper" 



:bed by Ikeno [ i ] in Marchantia. The cilia arise from the ble- 

 pharoplast a short distance back of the apex, and become finally about as 

 long as the body of the free spermatozoid, which is about i'v in length. 



The development of the spermatozoid in P. radiculosa was found to 

 be so much like that of /'. Zollingfri that no attempt was made to follow 

 it in .It-tail. However, some of the later stages in the last mitosis of the 

 spermatocyte, which were not seen in P. Zollingfri. were secured in P. 

 radiculosa. The nuclei are so small that difficulty was experienced 

 in d< 'ic number of chromosomes, which is probably eight 



(see l-'i- I-'. AM The spermatocytes are separate 



by a delicate membrane, which is more difficult to demonstrate 



