Bennet M. Allen ~ 89 
longitudinal canal remains incomplete, however, although it may unite 
several rete-cords in the manner shown. 
Young males taken at the time of hatching, show many of the rete- 
cords to have already acquired a lumen in places. The rete-cords of 
females at this age do not show a lumen, nor do they at any time, because 
they have already paused in development. They are, however, still 
recognizable. Up to this point no distinction of sex has been noted 
although well marked differences had begun to appear in the stage of 
13 mm. O-7. length. Close study has yet to be made to determine the 
earliest evidences of sex differentiation. 
It is not our aim to follow the later development of the rete-cords or 
sex-cords. In its general features, the further development of the sex- 
glands of the turtle shows many points of similarity to that in the mam- 
mals. The sex-cords degenerate in the female forming the medullary 
cords while the “cords of Pfliiger” arise as a later thickening of the 
germinal epithehum. In the males the sex-cords lengthen, assuming a 
more regular form and arrangement. Their thorough anastomosis with 
one another allows the semen to be poured from several into a common 
rete-cord. The mesonephros degenerates leaving a number of the urin- 
iferous tubules to function as vasa efferentia. In the adult male the rete- 
cords are found to be reduced in number, there being nine in the specimen 
studied while sixteen were counted on the right side of an embryo of 
C-T. 8 mm. length. No attempt was made to determine how or when 
this reduction was brought about. It is quite probable that some rete- 
cords are weak and become broken by shifting of the organs in the 
process of growth. In any case there is no systematic degeneration of 
the rete-cords in any particular region or regions along the sex-gland. 
SUMMARY AND CONCLUSIONS. 
The sex-cords are formed from irregular ingrowths of the germinal 
epithelium. It is not until relatively late in development that they take 
on the semblance of cords. They are made up of ordinary peritoneal cells, 
together with primitive sex-cells which are also found in the peritoneum 
at this stage. 
The rete-testis and rete-ovarii are formed by the union of funnel-cords 
with evaginations from the capsules of Bowman. ‘The funnel-cords are 
derived from the peritoneal funnels of the Malpighian corpuscles. They 
occupy a region lying along the lateral edge of the sex-gland, and not only 
co-extensive with the latter, but extending a short distance anterior to 
it. The bases of the funnel-cords may, or may not, be included in the 
sex-gland to form a part of the seminiferous tubules of the testis or 
