466 General Notes. 
the stapes to one side. This is exactly comparable to the relation — 
between the interstapedial and the stapes seen in the Sa lientia, ex- 
cept that the two elements are not actually connected as in Clepsy- 
drops. Paleontology then modifies the evidence from embryology, 
and renders it highly probable that the columella auris, interstape- 
dial and incus are homologous elements, and originated by segmen- 
tation from the proximal end of a ventral cranial arch, probably the _ 
ceratohyal. 
Seventh.—It follows, from what has preceded, that the condition 
of the representatives of the ossicula aiditus in the Urodela is one 
of a. 
Highth.—It becomes probable, but not certain, from the position of 
the spilt disc in the Rhachitomi at the proximal base of the 
quadrate bone, that the epistapedial cartilage has originated asa 
segmentation from the proximal extremity of the quadrate cartilage, 
‘and is therefore truly homologous with the mammalian malleus. 
'This-is, however, nothing more than a possibility —Z. D. Cope. 
EXPLANATION OF e a gr tis LAR AND SUSPENSORIAL 
MENTS OF BATRACHIA, 
Fig. 1. Zrimerorhachis insignis Cope, from below; ? natural 
size 
Fig. 2. Zatrachys serratus Cope, corresponding part of the skull 
to Fig. 1; opposite side from above; 2 natural size. 
Fig. 3. ’ Cryptobranchus allegheniensis Daud.; X 2; middle part 
of squamosal bone removed. 
Fig. 4. Diemyctylus viridescens Raf.; X 8; squamosal bone 
removed and represented at 2 a; 2 b, end of ceratohyal, showing 
se with hyoquadrate ligame nt. 
. Typhlonectes compressicauda D. and B.; from the Belize; 
3. 
Fig. 9. Amblystoma tigrinum Green, larva; X 4; squamosal 
bone ater eee and represented (under side) at Sq. 
4, 
Fig. 12. Rana virescens Kalm, larva; X 
Bh 13 ee catesbeiana Shaw ; larva more advanced than 
Fig. 1 
Fig. u odok — Green; X 6; squamosal bone 
removed and represented at 
ig. 15. Siren lacertina L. ; x 4. 
Fig. 16. Rana pretiosa Bd. Gird.; 2; auricular bones 
removed at a, the distal elements in section n. 
Explanation of Lettering. 
A. T., Annulus tympanicus; B. O., basioccipital; C. Br., S 
tobranchial; C. H. ` Ceratohyal ; Q Tr, Cornu trabeculi ; 'E. ve 
Epista ial ; Eth., Ethmoid; Ex. O., Exoccipital ; F. P., Fron Eo 
parietal; Hm., Hyomandibular; H. Qi s Hyo idal ligament; t 
