106 



Mr. Alban H. G. Doran on the 



[June 15, 



almost arctoid. On the other hand, the stapes has oftener fused crura 

 without any aperture (as in the dolphins) than in the Phocina. 



The walrus possesses a malleus with a head much like that of PJioca ; 

 but the articular surface is less abnormal in character, and above all the 

 manubrium is extremely short. The incus is phocine ; but in the stapes 

 Trichechus approaches Macrorliinus. 



The ossicula of Macrorliinus differ Tery markedly from those of Ci/sto- 

 lyliora ; in the malleus the former resembles Stenorhyncliiis, whilst in the 

 stapes it is more like Trichechus. The stapedes of Stenorhrinchus and Cys- 

 tophorcc are more of the Phoca type. In the Phocinae alone is seen a 

 second articulation bet^^-een the malleus and incus, and this feature is 

 not constant in every species. 



Among the Uis^gtjlata the laminated type of malleus prevails ; the pro- 

 cessus muscularis is rarely quite obsolete, but seldom very long. The 

 incus is very variable in form, and bears important distinguishing features 

 in certain families. A quadrilateral form of stapes, due to great breadth 

 of the head of that ossicle, occurs very frequently. 



Among the Perissodactyla Equus in its malleus least resembles the 

 remainder of the whole order, the head of that bone being well dev eloped 

 above the level of the articular surface as well as anteriorly, and the 

 lamina is almost obsolete. In the Ehinocerotidfe (where all the ossicula 

 are proportionally very small) and in the Tapirs the malleus has a 

 narro\A- lamina, not simply extending between the head and the processus 

 gracilis, but running for^^^ ards to the A'ery extremity of the latter. All 

 these animals have perfectly triangular stapedes, differing from the form 

 almost constant in the larger Artiodactyla. 



In the Tylopoda the malleus resembles that of the pig and its allies in 

 the great anterior development of its head ; but unhke those animals the 

 articular surface of that ossicle is wide and shallow, as in the Ehinoceros 

 on the one hand and the larger Euminants on the other ; but it most 

 resembles Bhinoceros in the ill-development of the processus muscularis 

 mallei and in the triangular form of the stapes. 



In the Suid^, in Hij)poiJotamus and Phacochceriis, the head of the 

 malleus is greatly produced forwards with a rather deep articular sur- 

 face ; the lamina and the processus muscularis are well developed. The 

 incus has a typical character ; the body is very square in form, with the 

 crura short, especially the posterior. The form of the articular surface 

 in JSi-ppojJotamus and in large specimens of Phacochcerus differs from 

 the same in the pigs. Hippopotamus, though so large, has a triangular 

 stapes, whilst that bone is quadrilateral in the Suida?, as in the ox and 

 adult sheep. 



In Tra.gulus the malleus is indistiuguishable from those of many small 

 antelopes and deer, the head not beiug produced forwards as in the 

 pigs ; whilst the incus retains to perfection the square body and short 

 posterior crus of the Suidoe. 



The Eovidae, Antilccaprid?e, Camelopardalid^e, and Cervidse are. re- 



