106 The Cephalic Veins and Sinuses of Reptiles 
The participation of all of these muscles must be demonstrated, however, 
by a study of the ejection of blood under natural conditions. 
Another undetermined point is the location of the opening through 
which ejection occurs. A suggestion in regard to this point has been 
obtained by manipulation. In vigorous specimens I have been able, in 
several cases, to force an ejection by compression of the two ven jugu- 
lares interne and elevation of the upper eyelid. The blood, in these 
cases, escaped from the membrana nictitans, which was thrown outward 
by the high blood-pressure in the sinus orbitalis. After the eye was 
restored to its normal condition there was no marked evidence of injury— 
no more than is to be observed when ejection occurs under normal condi- 
tions. A microscopic examination of specimens treated in this way 
showed an opening formed by rupture of the outer wall of the sinus 
membrane nictitantis. Whether the location of the opening is the same 
under natural conditions, must yet be decided. In a specimen observed 
by Hay, 92, p. 376, the blood “ was shot backward and appeared to issue 
from the outer canthus.” However, if the opening is in the membrane 
nictitans, its position with reference to the outer lids would be variable. 
I had hoped that the court plaster method employed in the investiga- 
tion of the moulting mechanism might furnish an opportunity to study 
the mode of ejection, but up to the present time this method has failed 
to cause an ejection, although the distension of the sinus orbitalis has 
been frequently observed in Phrynosoma. 
The failure of this method to induce ejection of blood would seem to 
oppose the idea of Stejneger, that the ejection occurs only during the 
moulting period, presumably as an aid to exuviation (see Hay, 92). 
2. Some of the facts mentioned in this paper throw light on the ques- 
tion concerning the function of the spongy tissue of the nasal cavity of 
mammals. In man this tissue is well developed in that part of the 
mucous membrane which covers the inferior turbinate bone. 
The most plausible theory hitherto suggested in regard to the function 
of this tissue is held by those who believe that the rich vascularization of 
the mucous membrane is necessary to give proper humidity to the in- 
spired air and to raise its temperature. To this theory objection has 
been raised by Arviset, 87, on the ground that such a function could be 
best performed by a rich network of capillaries near the surface of the 
mucous membrane, while it would not explain the presence of the deeper 
sinuses of the spongy tissue. Arviset concludes that if the spongy body 
gives warmth and moisture to the inspired air, such a function must be 
accessory. 
