466 MR. A. H. G. DORAN ON THE MORPHOLOGY 



outer and anterior projection), as in many other animals. The manubrium stands out 

 from the head completely external ; and its point is directed rather backwards : it is 

 separated from the rest of the malleus above by the groove on the outer aspect of the 

 ossicle; below it is blended with the base of the ridge continued from the processus 

 muscularis. It is wide at the root, and triangular in form; its upper border is very 

 broad, particularly towards the groove, and sharply bordered from the sides ; externally 

 it runs into the outer aspect by forming a prominent bold convexity, instead of a pro- 

 cessus brevis ; the outer aspect is also sharply defined, its borders being continued from 

 above, and towards the extremity it is spatulate : in some specimens this dilatation is 

 very marked, in others hardly perceptible. The sides of the manubrium are flattened, 

 and somewhat concave near the root ; the inner border is rather sharp, and quite concave ; 

 it blends with the head as aforesaid below the processus muscularis. It is wide at the 

 root, and triangular in form : its upper border is very broad, particularly towards the 

 groove, and sharply bordered from the sides ; externally it runs into the outer aspect by 

 forming a prominent bold convexity instead of a processus brevis ; the outer aspect is 

 also sharply defined, its borders being continued from above, and towards the extremity 

 it is spatulate ; in some specimens this dilatation is very marked, in others hardly per- 

 ceptible. The sides of the manubrium are flattened and somewhat concave near the 

 root ; the inner border is rather sharp, and quite concave, it bends with the head, as 

 aforesaid, below the processus muscularis. 



The incus of Salicore (PL LXIII. figs. 28, 29) is singularly placed, its " processus 

 brevis " being absolutely superior in position to the rest of the bone, instead of being 

 postero-superior, whilst the stapedial eras is equally inferior; the facets look directly 

 outwards on account of the internal position of those on the malleus. The body is twice 

 as wide as it is deep ; its inner aspect, which is wide, smooth, and convex, fits into a 

 depression in the petrous bone ; its articular surface consists of a concave reniform facet, 

 corresponding to the upper one on the malleus, separated by a sharp projecting angle 

 from two oval lower facets, which look towards each other, and are divided by a deep 

 groove, into which the projecting angle between the lower facets on the malleus is locked 

 in the recent skeleton. The posterior of the two lower incudal facets is borne on a very 

 prominent tubercle projecting from the outer and more posterior surface of the body of 

 the incus — a most characteristic feature, by which this ossicle in Salicore may be at once 

 distinguished from the same in Manatus, and apparently in Mhytina and Salicore. 



The processus brevis is very short, and lies above and somewhat anterior to the rest of 

 the ossicle ; it is firmly ankylosed to the petrous bone ; but being thin and brittle, the 

 whole incus is generally detached if the skull is dropped on the ground, or struck 

 violently after maceration. The processus longus arises far from the outer eras on 

 account of the great width of the body, to which it lies inferiorly and slightly posteriorly. 

 It is short, slightly curved, flattened extero-internally, and of almost equal thickness 

 throughout ; the oval disk at the extremity is generally separated from the rest of the 

 crus by a faint groove, so as really to represent the os orbiculare, the existence of which 

 in Salicore seems to be denied ; as a rule, the larger the mammal the less developed is 

 its Sylvian apophysis. 



