28 QUARTERLY CHRONICLE, 



With respect to the deyelopment of the spermatic bodies, 

 nearly all that is essential has been already communicated by 

 Schweigger-Seidel in the paper above cited ; and like that 

 observer, M. Valette St. George has been able to trace the 

 transformation of the nucleus of the sperm-cell into the rod- 

 shaped head, as well as the formation of the filament from 

 the cell-contents. The process may be well seen, he says, in 

 the Spotted Salamander. The nucleus becomes elongated 

 and transformed into the liead of the spermatozoon, being 

 frequently rolled ixp in the cell. Its outermost part forms a 

 distinctly defined appendage, O'OOSmm. long. 



The author proceeds to compare the result of his re- 

 searches on the development of the spermatozoon in the Ver- 

 tebrata with those of other observers — as Kolliker, Anker- 

 mann, Pfliiger, and Henle,'who, though agreeing with Kolliker 

 that the head of the spermatozoon is a metamorphosed 

 nucleus, conceives, nevertheless, that for the formation of 

 the tail a persistent connection of the head with the cell is 

 indispensable. He also notices the views of Grohe, who 

 considers the nucleus of the sperm-celFas merely a particle of 

 contractile substance, which he thinks it probable is de- 

 veloped spontaneously from the cell-contents.* According to 

 Schweigger-Seidel the spermatozoon is not a simple nuclear 

 formation, but corresponds, as a transformed one-rayed ciliate 

 cell, to an entire cell. Of the two kinds of cells found in the 

 tubuli seminiferi, only one kind "with minute clear nuclei 

 undergoes the transformation into spermatozoa. 



The author's own views, as above stated, appear to coin- 

 cide pretty nearly with those of Schweigger-Seidel, viz., 

 that the nucleus and the cell-contents are both engaged in 

 the formation of the spermatozoon. In the mammalia the 

 first change consists in the nucleus becoming more trans- 

 parent, and losing its granular contents, or exhibiting instead 

 a round nucleolus, wdiich in its turn disai:)pears. One half of 

 the nucleus then exhibits a thickened contour as well as an 

 appendage in the form of a nodule, Avhich may become 

 developed into a sort of cap. At the same time it becomes 

 elongated, and assumes a brilliant aspect, and now, or a 

 little before this, a filament sprouts out of the cell which 

 comes into connection with the nucleus. The cell substance 

 disappears by degrees, and idtimately becomes attached as a 

 smaller or larger aiipendage to that part of the filament 

 designated by Schweigger-Scidcl the " intermediate-piece." 



Some observations, but not of much importance, on the 



* " XJeber die Bewegung der Samenkorper." Von F. Grohe. Virchow's 

 * Archiv,' xxxii. 



