444 MR. LUBBOCK ON THE THYSANURA. 
My examination of Smynthurus began early in October. At this period the ovaries 
generally contained perfectly clear jelly-like nuclei, of which the largest were about 
*001" in diameter, but many were much smaller ; these nuclei were surrounded by a 
clear, transparent, but less brilliant substance, which sometimes formed a complete 
spherical envelope to a single nucleus, but generally appeared as a lobulated mass 
enclosing two or more. In other cases, which I suppose were more advanced, the nuclei 
were darkened by a deposit of granules. Even, however, early in October the development 
of the eggs was sometimes much more forward, and the ovary contained a number of yelk- 
masses at pretty regular intervals. In a transverse section of the ovary there were three, 
or at the broadest part four rows. The spaces between the yelk-masses were occupied, 
as before, by the nuclei and their transparent enveloping substance. The yelk-masses 
having at this period no bounding membrane, when I attempted to isolate them by open- 
ing the ovary, they immediately fell to pieces ; which made the study of their develop- 
ment somewhat difficult. On the 13th October I found a specimen with eggs apparently 
ready to be laid ; they were yellow, round bodies, *01" in diameter, with a single struc- 
tureless ovarian membrane, and the yelk was composed of oil-globules of various sizes 
up to -0015". I could find no trace of Purkinjean vesicle. On the 22nd I exa- 
mined another female in a similar condition, and found the eggs to be about forty in 
number. 
Male Generative Organs. — Smynthurus Buskii, as I have already observed, became 
much rarer in the latter part of November, and disappeared altogether early in December. 
Up to this time I had been occupied in the determination of species and the examination 
of the other parts ; so that my description of the male organs of reproduction must be 
taken from Papirius Saundersii, which made its appearance later in the autumn, and 
lived longer through the winter. There is, however, no doubt that, if my specimens had 
lasted, I should have been able to lay before the Society a description of these organs 
Smynthurus Buskti, which, from its greater size, was the species most favourable for 
dissection. 
In Papirius Saundersii, as in many other apterous Articulata, the testis is formed 
on the same type as the ovary. On each side of the body is a simple tube (PL XL\ L 
fig. 38 a), opening into a triangular reservoir with its base in front. The two posterior 
sides of the triangle are accompanied by a glandular accessory organ, containing a centra 
cavity (PL XLVI. fig. 38 c), full of minute globules, the largest of which do not exceed 
•000083" in diameter, while the majority were much smaller. From the posterior angle 
of the reservoir a short and narrow vas deferens runs into the ductus ej aculatorius, 
which is also short pyriform, and opens, like the vulva, with the anus at the posterior 
end of the body. 
The development of the spermatozoa proceeds as in OUsium (Phil. Trans. 18W- 
The testis contains small cells, about -00025" in length, and collected into masses ot 
in 
various sizes, which have probably arisen within mother-cells ; their size does n 
appear to depend in any way on the stage of development of the spermatozoa. The 
small cells which compose them are at first somewhat oval ; gradually one end elongates. 
and at length they resemble in form the q^ of a Cynips, consisting of a thread, wit i 
