204 WHEELER. [Vot. II. 
figures being preserved to enable one to recognize dividing nuclei 
at a glance. All the eggs were imbedded after treating with 
clove oil, in paraffine melting at about 55°C. The somewhat 
gummy yolk cut without any tendency to crumble, and perfect 
series of sections were obtained without the slightest difficulty. 
Staining on the slide with borax carmine gave beautiful results 
in all stages, but was resorted to only in young eggs, the vitel- 
line membranes of which did not stand off from the surface of 
the yolk, and in advanced embryos which had developed the 
larval cuticle. To save time, embryos in other stages were 
stained before imbedding, after removing the egg-envelopes. 
As much as possible of the borax carmine was extracted with 
acidulated 35 per cent alcohol. 
HISTORICAL. 
The cockroaches have long been favorite objects of morpho- 
logical study. Easily obtained at all seasons of the year, of 
convenient size for dissection, and being but slightly modified 
descendants of the oldest insects of geological time, they com- 
bine qualifications which make them especially interesting and 
valuable to the morphologist. Thus we find that no less than 
twenty investigators have sought material for anatomical and 
embryological study in the common species of Alattide. I will 
mention only those who have treated of the oogenesis and ontog- 
eny of Blatta and Periplaneta. 
Rathke (42) was the first to publish an account of the devel- 
opment of blatta germanica. Brandt (6) made a study of the 
ovarioles of Periplancta. UHuxley’s (22) account of the general 
anatomy of the same insect contains some valuable remarks on 
the ovaries. Kadyi (23) has given us a condensed account of 
the oviposition and micropyles of Pevzplaneta orientalis. Patten 
(38) in 1884 published a preliminary note on the development 
of Llatta. He observed that the first and second maxillz are 
at first triramous, and made some remarks on the heart and on 
the peculiar organs developed from the appendages of the first 
abdominal somite. Stuhlmann (45) treated of the degeneration 
of the germinal vesicle in Perzplaneta. During the same year 
(1886) also appeared Miall and Denny’s work (82) on the anat- 
omy of Periplaneta, containing Nusbaum’s brief embryological 
