In fbealoe at £•# os. (Fi&. Z) tho urogenital plate, * lch cx- 
tenda fro* the perl nets* to the tip of the phallus, is perforated by 
<& 
the posterior o© tinuution of the urogenital aimie lesson in the fors 
of a narrow elH to the exterior, attending saso ilata no® ventrally 
fron the perineuc, but leiving; tho ventral two-thirdf: of the plate filled 
with the epiibeliun of its walls. This plate extends along the dorsal 
surface of 4 h- phallus: to its tip. the prissordia of the fculbc-vestibular 
glands are already present, as o all latere out*»pouchin&e of the lining 
epiteliim of the two dorsal-grooves in the side walls of the s-rus. 
Bhil* only about 100 nicra long, they turn forward as distinct glased®, 
but are net sc far dorsad as in tho wale of thic siso# end are slightly 
ssore apparent. Frcr these * lands forward,.the clous, flattened ©u* 
laterally, bends all htiy war trad, and a ridge develops in its dorsal 
wall, extending farther into th luzsoa as one proceeds forward, till 
tho sinua itself hocc^es & narrow crescent in section outline where 
the Wolffian duet;, open into it. this they do by penetrating tho 
inror mj.ls of tisi" crescent from tho interior c the rid,? e. the 
* 
l&llerian du ts dnot reach the sinus at this stage, but they do at 
3. ' 03 . (Pig. 4), Just posterior to tho Wolffia ducts, the distance 
oo the urethra proper frewa ureters to olffian ducts is longer in the 
3.0 ci5. rta s. 
At 3.6 css* (Fig. 5). ths ctnua s a little longer, the bulbo- 
vestihular glands larger, d the sex ducts open into a sinus, oval 
in orosa-secticn. The urogenital ; late atil extend? tc the tip of 
the ph alloc, the po ter lor vulva opening has an: urged t» all ii~ 
mmionc , asd is : open for alnost tha entire depth of the plate, 
the dietaoo ofl Ih© mi sthm ureters to the Wolffian ducts, 
is longer, th© porfneu*. i~ a little wider, and the phallus, a little 
Tsoro recurved, than i.i younger stages. *h® - ttlc regions of growth 
behi d the vagina are now incorporatec into it. 
At 5.1 o • the urogenital piste extends forward into the tip of 
