6 MARY L. WALKER ON THE ECHIDNA AND ORNITHORHYNCHUS. 
Cetacea, the Mole, Hedgehog, Horse, and other forms.* Immediately below the 
larynx two thick rounded processes project downwards from the lateral walls of the 
cesophagus, and behind each there is a deep sinus. The purpose of these last struc- 
tures is not apparent. 
In Ornithorhynchus the epiglottis is thick, broad, pointed above, and carti- 
laginous. 
*Cf. Hows. On a Rabbit with an intranarial epigiottis. Journ. of Anat. and Phys., Jan. 1889, 
which paper reached us when this was in proof. 
DESCRIPTION OF THE PLATE. 
H. Body or copula of the Hyoid. H'. Anterior hyoid cornua. HH”. Posterior cornua. 
9. Body or copula of the Thyroid. 6. Anterior thyroid cornua. 6. Posterior cornua. 
C. Cricoid cartilage. A. Arytenoid; m, its accessory nodules in Ornithorhynchus. Pe. Procricoid 
cartilages in Echidna. Tr. Trachea. E. Epiglottis. 
ih. interhyoid muscle, ¢.t. interthyroid, 4. thyro-hyoid, ¢.t. crico-thyroid, p. posterior thyro-arytenoid, 
and crico-arytenoid, 7. lateral thyro-arytenoid and crico-arytenoid, a. aryteno-procricoid. 
Fig. 1. Larynx and hyoid of Echidna, ventral view. 
Fig. Larynx and hyoid of Echidna, lateral view. 
Fig. Larynx of Ornithorhynchus, ventral view. 
Larynx of Ornithorhynchus, lateral view. 
. Larynx of Echidna, dorsal aspect, after removal of the thyroid cartilages. 
Larynx of Ornithorhynchus. 
Diagram of muscles in Echidna, lateral aspect. 
. Diagram of posterior thyro-arytenoid, posterior crico-arytenoid, and procrico-arytenoid in Echidna. 
ty 
a 
oe) 
OMAID oa fF WW + 
. Diagram of lateral thyro-arytenoid and lateral crico-arytenoid in Echidna. 
Fig. 9a.View of glottis in Echidna, exposed by opening up the posterior wall of the pharynx. G. tongue. 
dp. placed upon the soft palate, lies in the posterior nares. fp. (at the base of the tongue), 
points towards the food-passage on the ventral side of the soft palate. E. epiglottis. pr. 
processes projecting from the cesophageal wall. 
Fig. 10. Epiglottis of Ornithorhynchus. 
