600 EDWARD PHELPS ALLIS, JR. 
of the palatoquadrate immediately posterior to the root of the 
processus basalis. The postero-mesial end of the hyomandibula 
has fused with the auditory capsule at the posterior edge of what 
Krawetz calls the foramen for the N. recurrens and R. hyoman- 
dibularis N. facialis, this foramen being the posterior opening of 
the trigemino-facialis chamber of my determinations (Allis ’14 ec). 
A little dorsal process of the hyomandibula (Ph) partly encloses, 
externally, the vena jugularis, and this little process will hereafter 
be referred to as the cartilage Ja. The connective tissue strand 
which connected the hyomandibula (Ph) and symplectic (Hz) in 
earlier stages is said to have now completely disappeared, and the 
hyomandibula (Ph) is here referred to (1. ¢., p. 8357) as ‘‘ein neues 
Knorpelstiick”’ although it is evidently the same cartilage as 
the similarly named one of earlier stages. It is said by Krawetz 
to be a seriat homologue of the epibranchials of his descriptions; 
but it is to be especially noted that these so-called epibranchials 
(1. ¢., fig. 10a) le at an appreciable distance dorsal to the so- 
called ceratobranchials, the two sets of cartilages having appar- 
ently chondrified independently of each other instead of as a 
single piece which later segments, which is so frequently said to 
- be the invariable rule, in all fishes, for the epal and ceratal ele- 
ments of the branchial arches, and less frequently for the pharyn- 
geal and hypal elements. These so-called epibranchials of Kra- 
wetz’s descriptions may then be pharyngobranchials, and Greil’s 
(18) description of them, to be given later, seems to confirm this 
conclusion. The so-called epibranchial of the second branchial 
arch is said by Krawetz frequently to come into contact with 
the wall of the auditory capsule, separated from it by only a 
delicate epichondrial membrane, and in the adult, as already 
stated, I find the dorsal end of what is certainly the epibranchial 
of this arch, and also that of the first branchial arch, in contact 
with the neurocranium. 
In embryos slightly older than Stage 48, the hyomandibula 
(Ph) is shown by Krawetz (1. ¢., fig. 6) extending entirely across 
the posterior opening of the trigemino-facialis chamber, and from 
the middle of this cartilaginous cross-bar the little dorsal process 
(Ia) of the preceding stage has extended dorsally and is said to 
