180 FRANCIS VILLY. 



by Professor Parker, receives no support from these researches ; but 

 it seems probable that the columella is not only physiologically but 

 morphologically to be associated with the ear capsule, and with it 

 alone. 



EXPLANATION OF PLATES XL and XII. 



Illustrating Mr. Francis Villy's paper on " The Development of the 

 Ear and Accessory Organs in the Common Frog." 



Alphabetical List of Reference Letters. 



A. C. Annular cartilage. A. C. H. Anterior cornu of the hyoid. 

 Am. A. Ampulla of the anterior vertical canal. An. C. Anterior 

 vertical canal. Au. C. Auditory capsule. Au. E. Auditory epi- 

 thelium. Au. G. Auditory ganglion. Au. I. Auditory invagination. 

 Au. N. Auditory nerve. Au. V. Auditory vesicle. B. Basi-hyal 

 cartilage. B. C. Body-cavity. Br. Brain. Br. A. 1, 2, 3, 4. 

 Branchial arches. Br. C. 1, 2, 3, 4. Branchial clefts. C. Cerebellum. 

 Cb. Cerebral hemispheres. Cd. Choroid plexus. Ch. Cochlea. Ch. 1. 

 Lagena. Ch. 2. Pars neglecta. Ch. 3. Pars basilaris. CI. Columella. 

 Cr. Cornea. D. A. Dorsal aorta. E. Eye. Ep. A. Epithelium of 

 the two anterior ampulla?. Ep. C. Epicoracoid. Eu. Eustachian 

 tube. F. Fenestra ovalis. G. G. Gasserian ganglion. G. N. Glosso- 

 pharyngeal nerve. Gu. Gullet. Kb. Hind-brain. Ho. A. Ampulla 

 of the horizontal canal. Ho. C. Horizontal canal. Hp. Hypoblast. 

 Hu. Humerus. Hy. A. Hyoid arch. Hy. M. Hyomandibular cleft. 

 In. Interstapedial cartilage. Ir. Iris. K. Kidney. L. Lens. 

 Md. Mandibular arch. ML Meckel's cartilage. Mo. Mouth. Ms. 

 Mesostapedial cartilage. Ne. Nervous layer of epiblast. N. G. 

 Neural groove. No. Nose. Nt. Notochord. 01. N. Olfactory 

 nerve. Op. 1. Optic lobes. Op. N. Optic nerve. Ot. E. Outer 

 layer of epiblast. Pa. pt. Palatopterygoid bar. Be. Precoracoid. 

 Be. 1. Perilymphatic canal (connected with the lagena). Be. 2. 

 Perilymphatic canal (connected with the teg. vase). B. V. A. 



