DR. J. MURIE ON THE FORM AND STRUCTURE OF THE MANATEE. 165 
catory and lingual apparatus, then, I propose to append to the remarks of Rapp, Vrolik, 
and Stannius reference to sketches of the palatal and mandibular arches. ‘These I have 
had illustrated, I believe for the first time, both as viewed in conjunction, in a longi- 
tudinal vertical section (fig. 37, Pl. XX VI.), and as separated (Pl. XXII. figs. 18 & 19). 
I shall also offer some observations on the composition of the parts, particularly as 
respects the so-called horny pints and their bearings towards those of the edentulous 
Rhytina stelleri. 
If the section made lengthwise through the cranium, and slightly to the left of the 
median vertical line, as given in fig. 37, be examined, the relations of the parts will be 
easily comprehended. Confining a survey to the mouth-cavity, the lower lip, with its 
sinuous, bristle-clad, thick epidermis, points forwards. Each bristle springs from a 
considerable-sized lenticular hair-sac. The fibro-muscular tissues beneath are unusually 
well developed. The mandibular pad (7. ¢. inner lower lip) is composed deeply of a 
thick gristly or fibrous layer, and a thinner superincumbent epidermis. In front it is 
separated from the outer lip by a deepish furrow, and behind stops short at the tip of 
the tongue, though, as afterwards shall be shown, it is continuous with the gums. The 
tongue is bound down behind the pad, and is incapable of being protruded. Forwards, 
from the soft membranous uvular curtain, the fleshy palate, to just in front of the 
molars, is only moderately thick, whence it by degrees increases in thickness and fills 
the deep concavity of the premaxillary bones, its anterior smoother portion forming the 
upper inner lip-pad. This latter is separated by a deep furrow from the true bearded 
lip and truncated muzzle. The palate and the said pad are equally made up of a thick 
substratum of firm fibro-elastic material overlain by much thinner derm and epiderm. 
What has been termed the horny plate is alone distinguishable by warty elevations. 
The lips and cheeks, from opposite the superior pad backwards to the front molar, have 
a clothing of long stiffish hairs, thickest set along the outer border of the gum; these 
are chiefly directed downwards and backwards. 
Turning now to the view of the mandible when removed (fig. 18), the outer true lip 
is notably dotted with short truncated bristles and longer hairs. The coriaceous pad 
has a deep and straight longitudinal median groove its whole length. Each moiety of 
this is again partially divided by a wavy but shallower furrow, which anteriorly and 
posteriorly curves outwards. The outer raised segments of the pad are only moderately 
roughened—but the inner ones remarkably so, being studded with short, erect, hard 
papillz of two sorts. The larger kind are conical, and about 0°5 inch high; the 
smaller setose sort are nearly as long, and abundantly fill the interstices between the 
first mentioned. 
The tongue quite agrees with Rapp’s statement, having long brush-like retroverted 
filiform papille towards the tip, many irregularly dispersed and different-sized fungi- 
form papillz, and a very numerous, closely arranged, double set of circumvallate glands 
situate at the root. The series of circumvallate, as noted by him, also extends linearly 
