528 The American Naturalist. > [June, 
EMBRYOLOGY.’ 
Ookinesis in Limax maximus.—The observations here given 
are confined to early stages of the egg while in the oviduct, and before 
the expulsion of either polar globule. The article, therefore, deals 
with stages which, for the most part, preceed any discussed by Dr. 
Mark in his excellent treatise on L. campestris. 
Of the following wood-cuts, Fig. 1 is a diagrammatic representation 
of the oviduct from a laying animal, from which eggs were taken, and 
studied serially as numbered. The vitellus averaged 156.2 » in diameter. 
, 4, Various methods were made use 
< of in fixing—Fols solution : osmic 
acid, 1 %, followed by Merkel’s 
faction was as follows: The body 
cavity of a laying animal was 
opened by a quick cut of the scis- 
sors, and the animal plunged into a 
boiling hot solution of corrosive sub- 
limate; allowed to remain one minute; transferred to water and eggs 
removed from oviduct and shelled? Vitellus allowed to remain in 
distilled water two minutes, then transferred to 35 and 50 % alcohol, 
remaining three minutes in each grade; then to 70 % alcohol for per- 
manent preservation. I found that if eggs were allowed to remain in 
distilled water three hours or more, they shelled better, the vitellus 
coming out clearer and freer. For examination of eggs in toto, Czokor’s 
alum cochineal gave, as a rule, good results. ‘Ten minutes’ stay in this 
dye appeared to give the necessasy differentiation ; but for examination 
of sections much longer time was necessary, two to three hours or more. 
Picrocarminate of lithium was also found to be excellent, if anything, 
better than Czokor, on account of its differentiating nucleus structures. 
‘Edited by E. A. Andrews, Baltimore Md., to whom communications may be 
addressed. 
2? “The Maturation, Fecundation and Segmentation of Limax campestris Bin- 
ney,” by E. L. Mark, Bulletin of the Museum of Comparative Anatomy, Vol. 6, 
parts 11 and 12, Cambridge, Mass, 1881 
* In the upper part of the glandular portion of the oviduct there were a number 
of eggs in which the outer membrane or shell was barely formed, in some, €88 No. 
1, for example, there was no membrane at all, and in others only the inner mem” - 
branous coat was present. 
