148 EDWARD L. RICE 
two as described in Chelydra by Nick (12, citing and confirming 
Siebenrock, ’97). 
Foramen endolymphaticum and ‘holes’ due to retarded chon- 
drification (fig. 8, f.end.). In stage 5 of Eumeces the foramen 
endolymphaticum is remarkably elongate in a direction approxi- 
mately parallel to the fissura metotica. The ductus endolymph- 
aticus leaves the ear capsule through the anteroventral end of 
the foramen, the posterior portion of the slit being filled out with 
a confused mass of procartilage and connective tissue which - 
makes the exact determination of boundaries extremely difficult. 
Owing to this fact, the size of the aperture may well have been 
exaggerated in the modeling; in a second model from the same 
sections (fig. 1) the foramen was represented as somewhat shorter, 
and, on one side, as divided by a bar of rather questionable 
cartilage. But, after all allowances, the large size and elongate 
form of the foramen endolymphaticum in this and earlier stages 
are beyond question. A comparison with stage 6 shows that the 
condition figured is only temporary, the foramen in the later 
series being circular or nearly so, and only large enough to permit 
the passage of the slender duct. The major part of the slit in 
the earlier stages is due to a mere retardation of the cartilage 
development, and its later filling in with cartilage is to be inter- 
preted as the further progress of the process, described in the 
preceding paragraph, by which the foramen endolymphaticum 
was originally separated from the acusticus foramina. An 
exactly similar change in the form and size of this foramen is 
described in the pig by Mead (’09). In Chelone and Dermo- 
chelys, but not in Chelydra, Nick (’12) reports a degeneration 
of the saccus endolymphaticus in later stages, accompanied by 
the complete obliteration of the foramen endolymphaticum. 
A similar delay in chondrification is responsible for the hole 
(‘Liicke’) described by Gaupp in the cochlear prominence of 
Lacerta. Other such holes have been reported in various parts 
of the otic capsule by Kunkel (’12 b) in some specimens of Emys, 
by Nick (712) on one side in a single specimen of Chelydra, and 
by Peyer (712) in Vipera. In stage 5 of Eumeces similar minute 
