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considered as simply a part of the palatine, pterygoid or palato- 
pterygoid part of the entire cartilage, according to the nomenclature 
employed, the part of the cartilage so designated including all that 
part of the palato-quadrate that lies anterior to the so-called otic 
process. 
Of these several terms I shall employ, in the following descrip- 
tions, the term palato-quadrate for the entire cartilage, considering 
it to be an abbreviation of the longer and more correct term palato- 
pterygo-quadrate; and, for reasons that will later appear, I shall call 
the anterior one of the two processes on its dorso-mesial edge the 
orbital process, the posterior one the otic process, and that part of 
the entire cartilage that lies anterior to the orbital process the palatine 
process. 
The palatine process of Chlamydoselachus, as thus defined, is a 
curved flat plate of cartilage, of nearly even width, that projects antero- 
n.esially beneath the anterior end of the neurocranium, as indicated 
but not well shown in Garman’s (1885) and Goopry’s (1910) figures 
of this fish. The dorso-lateral surface of the process rests, when the 
mouth is closed, against the ventral surface of the lateral edge of the 
solum nasi (Aruıs, 1913), the line of contact extending anteriorly and 
slightly n.esially along the dorso-lateral surface of the process from 
about the level of the base of the orbital process. Mesial to this line 
of contact with the solum nasi, the process is “twisted,” as GARMAN 
describes it, so that its anterior portion lies in a nearly horizontal 
plane, with its dorso-lateral (external) surface directed dorsally, and 
it meets in the median line, and is firmly bound by tissue to, its fellow 
of the opposite side; the two processes together forming a nearly 
horizontal shelf across the anterior portion of the large and deep 
subethmoidal depression on the ventral surface of the neurocranium. 
This subethmoidal depression is shown in both Garman’s and GooDEY’s 
figures, but is not there as pronounced as I find it in all of the several 
specimens that I have examined. It occupies the full width of the 
ethn.oidal region of the neurocranium, and extends from the tip of 
the rostral process to that marked angle in the mid-ventral line of 
the basis cranii that GEGENBAUR (1872) described in other selachians 
as the basal corner (Basalecke). 
The mucous membrane of the mouth cavity lines the walls of 
the subethmoidal depression and is then reflected, first posteriorly 
and then anteriorly, to clothe first the dorsal and then the ventral 
