* 
1202 The American Naturalist. [December, 
cells are also modified epithelial cells of the body-cavity, and this 
agreement adds unquestioned weight to the opinion that the insects 
stand in phylogenetic connection with the Annelids. 
The genital anlage takes its origin from these genital cells together 
with certain smaller ones,—the ** epethelial’’ cells of the entomologists. 
It is elongated and paired in both sexes, and lies either side of the 
intestine; the numerous egg-tubes which comprise the ovary of the 
female arise from these two cell-strands. With regard to the parts 
composing the ovarian tubes Herr Heymons does not agree with former 
authors. He states that the epithelial are of an entirely different 
origin from the eggs, whereas they were hitherto held to be of like 
origin,—at first an undifferentiated mass of cells, which afterwards 
gradually separate into egg and epithelial cells ; and while the whole 
genital anlage of the females goes to form the ovarium, only a portion 
of the same is used in the male to build the testes. According to the 
investigations of Herr Heymons the origin of the sexual glands is alike 
in the male to that of the female already described: thetwo lateral cell- 
bands are formed, each of which is held in place by an ** endfaden- 
platte." Both genital and epithelial cells are present. A large num- 
ber of the latter lie on the ventral side of the organ, and give rise to 
the vas deferens. Ata particular stage of the development the geni- 
tal cells of the male group themselves at four points. These are first 
rudiments of the four follicles which compose each testis. Each geni- 
tal anlange now contains two portions: (1) the four follicles, and (2) 
the genital and epithelial cells, which did not enter into the composi- 
tion of the first, but which can be clearly seen between them. The 
follicles are connected with the vas deferens, which becomes shorter, 
and thus draws them out of the mass. The above-mentioned cells 
which were between the follicles are held in position by the ** end- 
fadenplatte,’’ and represent, as Herr Heymons has most conclusively 
shown, the rudiment of a female genital gland, The further develop- 
ment of this organ is very variable in different individuals ; details 
may be found in the paper itself. Of special interest is the fact that 
Herr Heymons found some cases in which the males possessed typical 
ovarian tubes with eggs and follicle, and that these were developed 
near the testes follicles, According to this the anlage of the male 
glands in the Phyllodromia must be regarded as hermaphro- 
tic. 
As the roaches are among the simplest and earliest insects, Herr 
Heymons draws the conclusion that the latter are probably descended. 
from hermaphroditic forms. 
