638 
e!, and /’, over its expansion; g, a branch of the vesti- 
bule cut across; h, //, the cartilaginous cranium; i, tym- 
panie cayity; k, pia mater; &’, bloodvessels from k 
plunging into the mass of the brain; /, dura mater; m, 
vessels of the median sinus; 7, fibrous membrane of the 
palate; n/, lateral sinus of the fibro-muscular membrane 
of the mouth; 0, windpipe; p, os hyoides; g, muscular 
bundles; r, adductor muscles of the neck; 7/, muscles of 
the lower jaw; s, bloodvessels cut across; t, dense white 
fibrous corium; u, epidermis very much wrinkled. 
Fig. 8; compare wood-cut 8, p. 577. Transverse section 
through the hemispheres, the optic lobe, and the lower jaw, 
just behind the opening of the windpipe; 5 diam. Cor- 
responds to the line C, in w-e. 3, p. 576; compare also 
fig. 4. 
hemisphere, the rudimentary corpus striatum lies at the 
View from before, looking backwards; a, left 
point where the letter is placed ; a!’, crura cerebri; 0, 0, 
interior face of the hemispheres; } is partly cut away to 
expose the bloodvessel (c’) going to the choroid plexus, 
(d,) which enters by the foramen at this point; c, blood- 
vessel which enters atc’; d, choroid plexus; e, third ven- 
tricle in the distance; f, 7’, optic lobes; g, inferior com- 
missure of f and /’; h, parietal bone of the skull; 1’, 
frontal bone; 7, sphenoid bone; j, cavity of the mouth; 
k, fibro-muscular layer of the floor of the mouth; 2’, 
roof of the mouth; J, windpipe; m, middle part of 
the hyoid bone; 7, bloodvessels; 0, muscular bundles; p, 
p!, pl!, three parts of the lower jaw, p still cartilaginous, 
the two others quite gritty with lime; q, fibrous corium. 
Fig. 9; compare wood-cut 9, p.577. The same section as fig. 
8, looking forward on the opposite side of the cut toward 
the olfactory lobes; 5 diam. ; !’, open communication be- 
tween the hemispheres; d/’, narrow passage in the olfac- 
tory lobe in the distance ; e’, anterior commissure of the 
optic lobes. The other letters as in fig. 8. 
Fig. 10; compare wood-cut 10, p. 577. Transverse section 
through the anterior end of the olfactory lobe and a 
portion of the surrounding tissues, seen from behind ; 
15 diam. Corresponds to the line B, in w-e. 3, p. 
676; compare also fig. 4: a, the right olfactory lobe, 
marked by concentric layers of alternately white and 
gray substance, the white being much thicker than the 
gray; 5, ventricle in the centre of the lobe; c, the vas- 
cular pia mater; d, arachnoid membrane, or network of 
vessels connecting the pia mater (c) to the dura mater 
(d') ; e, interorbital septum ; /, frontal bone; g, fibrous 
EXPLANATION OF THE PLATES. 
fig. 4: a, right Schneiderian membrane ; that part which 
is below the palate bone (f) is not seen in the longitu- 
dinal section, (fig. 4,) which is made through the middle 
line of the head; }, septum narium; 0/, the irregular 
dotted line next to a indicates a dense layer of black pig- 
ment; c, frontal bone; d, ethmoid; d/, upper edge of 
the intermaxillary bone, os incisivum ; e, corium; f, vo- 
mer; g, palate; h, inner edge of the horny layer of the 
mandible, where it meets the mucous membrane (7) of 
the palate (g). 
PLATE XXIV. 
[Fig. 7, 7a, 9, 9a, 15, from nature, by A. Sonrel; the others by 
H. J. Clark.] 
Fig. 8 and 14 are from Nanemys guttata; the others from 
Chelydra serpentina. 
Fig. 1, 1a, 2, 2a, 3, 8a, 4, 5, 7, 7a, 8, 9, 9a, 11, 12, 18, 18a, 14, 
15, are all lettered in the same manner: a, amnios; a’, 
caudal hood; e, edge of the channel of the spinal mar- 
row; ¢, edge of the open part of the brain; e%, brain 
closed over; e°, constriction between the corpora quadri- 
gemina and the optic lobes; /, vertebra; /1, vertebral 
layer; f°, lower edge of /; f°, lower edge of f*; /', 
upper edge of f; ’, aortic bulb; 2°, auricle ; i‘, ventri- 
cle; i, vena afferens; 7, abdominal veins; 7°, cephalic 
veins; j, cephalic artery; j*, dorsal artery; &, the whole 
eye, or the outer layer of the retina; 4’, the inner infolded 
layer; i*, passage to the brain; 4°, crystalline lens; 7, 
point where the inner wall (x*) folds upon the outer () ; 
l, ear ; m, branchial fissures ; 7, intestino-subsidiary layer ; 
n®, stomach; n‘, esophagus; n°, anus; n°, allantois; 0, 
edge of the abdominal aperture; p, musculo-cutaneous 
layer; 7, liver; ¢, windpipe; /, lungs; », nostrils; w, 
fore legs; w', hind legs; z, mouth; 1, outer wall of 
the lungs; 1/, outer wall of the esophagus behind 
the lungs; 1//, outer wall of the esophagus before the 
lungs; 1///, outer wall of the windpipe ; 2, mucous mem- 
brane of the lungs; 2/, mucous membrane of the wsoph- 
agus behind the lungs; 2/’, mucous membrane of the 
esophagus before the lungs; 2/’’, mucous membrane of 
the windpipe; 3, opening of the windpipe; 5, open com- 
munication between the windpipe and the cesophagus ; 
6, part of the trachea of the right lung; 7, a bronchiole 
trending transversely to the broad face of the lung. 
corium; h, layer of pigment under 7; 7, the epidermis. Fig. 1. The lungs, and part of the esophagus, from below, 
Fig. 11; compare wood-cut 11, p. 557. ‘Transverse section 40 diam., date not ascertained; fig. 1a, interior walls of 
through the nasal cavity, seen from behind; 5 diam. Cor- fig. 1; 250 diam. 
responds to the line A, in w-c. 8, p. 576; compare also | Fig. 2. Lungs and stomach, from below, about 5 diam.; laid 
P I ’ I c=] c=) ? 

