328 M. D. HILL. 
Finally, I may mention that the process I have described, 
viz. the homogeneous middle-piece of the spermatozoon be- 
coming first the granular, then the reticular, and finally again 
the homogeneous central mass of the astrosphere (figs. 3, 4, 5, 
and 6 for Echinus, and figs. 14, 15, 17, 18, and 19 for Phal- 
lusia) is almost exactly the same as Vejdoffsky described for 
Rhynchelmis. From these results he believes that protoplasm 
is at first quite homogeneous and structureless; that then very 
small granules appear which group themselves together to form 
a reticulum, which may become once more homogeneous. I 
do not pretend, however, to use this word “ homogeneous” 
other than as before explained, in a purely relative sense. 
With higher powers of the microscope I see no reason to sup- 
pose that the middle-piece would not itself present a “ Waben- 
structur,” and that the network is anything more than a coarse 
protoplasmic reticulum. It is right, moreover, to mention 
that I was not biased by Vejdoffsky’s work when noting the 
above process, for my attention was not drawn to this parti- 
cular point until reading his paper again after my own had 
been finished and sent in for publication. 
A point worthy of notice is that, at least in one particular 
instance (fig. 14), the homogeneity of the central mass has 
been arrived at before the division of the spermastrosphere. 
M. D. Hitt. 
June, 1895. 
List oF WORKS REFERRED TO. 
1. Boveri, Ta.— Befruchtung,” ‘Erg. der. Anat. u. Entw.,’ Merkel and 
Bonnet, Band i, 1891. 
2. Bovert, Tu.—‘Zellen Studien,’ i—iii, 1887, 1888, 1890, Jena. 
3. Firox, R.—** Ueber die Reifung und Befruchtung des Axolotleies,” ‘ Zeit. 
wiss. Zool.,’ Bd. lxv, 1893. 
4. Fou, H.—“ Le Quadrille des Centres,” ‘Arch. Sci. Phys. et Nat.,’ xxv, 
1891. 
