No. 3.— Amitosis in the Embryonal Envelopes of the Scorpion. 
By H. P. Jonson." 
In the fall of 1889, at the suggestion of my instructor, Prof. E. L. 
Mark, I decided to work upon the problem of the so-called “ direct ” or 
amitotic division of nuclei. While in search of suitable material, my 
attention was called to a brief article by Blochmann (785), describing a 
very well marked amitotie division for the large nuclei of the embry- 
onal membrane of the scorpion. A number of Centrurus embryos 
were kindly given to me by my friend, Dr. G. H. Parker. These em- 
bryos had lain in 90% alcohol since the summer of 1886. The mode 
of fixation (for the purpose of studying the development of the eyes) 
was somewhat unusual; for, immediately after their removal from the 
mother, they were immersed in 35% alcohol, and thence carried up 
quite rapidly, through 50 and 70%, to 90%. Notwithstanding this 
rather crude method, the membranes were in excellent histological 
condition, in no way inferior to material afterwards prepared by the 
most approved methods of fixation. 
In addition to the material above mentioned, I received from Mr. 
Richard Goeth, of Burnet County, Texas, during the following winter 
and spring, about three dozen live specimens of Centrwrus (sp. incog.).? 
A lot that arrived in the latter part of May contained several pregnant 
females, with embryos in different stages. The scorpions were chloro- 
formed, and the ovarian tubes with the embryos enclosed were dissected 
out as quickly as possible. A number of killing agents were used, 
including Flemming’s weaker chrom-aceto-osmic, Rabl’s chrom-formic, 
Perenyi’s fluid, Kleinenberg’s picro-sulphuric, and Merkel’s fluid. 
For staining, I have used chiefly Ehrlich’s hematoxylin. Grena- 
cher’s alcoholic borax-carmine and Czokor’s alum-cochineal have given 
fair results. Safranin, employed according to Flemming’s method, I 
1 Contributions from the Zoölogical Laboratory of the Museum of Comparative 
Zoölogy, under the direction of E. L. Mark, No. XXX. 
2 This is the species used by G. H. Parker in his study on the development of 
the eyes (see Bull. Mus. Comp. Zoöl., Vol. XII. No. 6, p. 173, 1887), and was then 
undescribed. I am not aware that it has since received a name. 
VOL. XXII. — NO. 3. 
