10 Osteology of Porzana Carolina. 
this orifice is overshadowed by a jutting ledge, developed 
by the ilium above, much as we find it in Geococcyx calt- 
fornianus, though not quite as manifest. A deep trian- 
gular notch defines, upon the posterior pelvic border, the 
landmark between ilium and ischium. This latter element 
does not meet the rib-like postpubis behind, being sepa- 
rated from it by quite an interval. Nor is the obturator 
foramen closed by the same means in front, as is often the 
case. 
On the under side of the pelvis, we find the sacral sweil 
to accommodate the enlargement of the myelon, to be very 
marked, coming out as it does to the very external iliac 
borders. That vertebra which is opposite the bony division 
between the cotyloid ring and ischiac foramen, throws out 
its apophysial struts as lateral pelvic supports at this point. 
Posteriorly, reduplication of the ilia forwards, form deep 
fossee, one on either side, at the back part of the pelvic 
basin, these being separated by the last two sacral vertebrz 
which are specially modified for that purpose. 
From my description it will be seen that Porzana and 
Geococcyx possess many points in common in their pelvis. 
1. Both have the same form of the sacral crista in 
front. 
2. Both have the same pattern, a peculiar one, of the 
pre-acetabular portion of the ilum. 
3. Each has a propubis, and the postpubis does not ex- 
tend much beyond the ischium behind. 
4. In each the ilium develops an overhanging ledge pos- 
teriorly, and the ischiac foramen is sub-circular in outline. 
5. The ilia extend beyond the sacrum posteriorly, and at 
the posterior borders behind, a notch shows where these 
bones join the ischia. 
With respect to the propubis, Professor Marsh says, in 
his work upon the Odontornithes, that ‘‘the remnant of 
the reptilian pubis is still plainly to be seen, especially in 
Geococcyx. It is not improbable that the retention of this 
process may be due in part to the habits of certain species, 
as it seems to best developed in running birds, and those 
that especially use the posterior limbs.” (p. 72.) 
As the Rails are great runners, too, it would seem that 
