224 The Anatomy of a 12-mm. Pig 
EXPLANATION OF PLATES. 
PLATE I.—Pig Embryo of 12.0 mm. Reconstruction from transverse sec- 
tions, Series 5. 
To show especially the cephalic nerves. c. 1, c. 2, c. 8, Cervical nerves. 
Chl, Cerebellum. com, Ganglionie commissure. Dien, Diencephalon. ex, 
External branch of the spinal accessory nerve. Ff, Froriep’s ganglion. G. 5, 
Gasserian ganglion. H, Cerebral hemisphere. j, Jugular ganglion. J, Lens. 
M. b, Mid-brain. Mdb., Mandibular process. Md. ob, Medulla oblongata. 
Mx, Maxillary process. n, Ganglion nodosum. Na, Nasal pit. Op, Optic 
cup. Of, Otocyst. Mec. 1, Recurrent laryngeal nerve. Ven. IV, Roof of 
fourth ventricle. 3, Oculomotor nerve. 4, Trochlear nerve. J5op, Branches 
of the ophthalmic division of the trigeminal nerve. 6, Abducens nerve. 7, 
Geniculate ganglion of the facial nerve. 8, Vestibular ganglion. 9, Petrosal 
ganglion. 10, Vagus nerve. 11, Spinal accessory nerve. 12, Hypoglossal 
nerve. ——— x 20 diams. 
PLATE II].—Pig Embryo of 12.0 mm. Reconstruction from transverse sec- 
tions, Series 5. 
The embryo has been drawn as if transparent to show the form of its 
pharynx, and the relations of the pharyngeal gill pouches to the grooves 
on the outer surface of the embryo. car, Carotid gland. Cbl, Cerebellum. 
CS, Cervical sinus. Dien, Diencephalon. H, Cerebral hemisphere. Hy, Hy- 
pophysis. Inf, Infundibular gland. Lat. Th, Lateral thyroid. 1. gr, Lachry- 
mal groove. m, Maxillary process. JM. b, Mid-brain. Mdb, Mandibular pro- 
cess. Jd. ob, Medulla oblongata. nda. er, External naris. ni, Internal naris, 
closed by an epithelial plate. Oe, Oesophagus. Op, Eye. Ot, Otocyst. Sp. ce, 
Spinal cord. Th, Median thyroid gland. thym, Thymus. Tra, Trachea. 1, 
2, 3, 4, Entodermal pouches of the corresponding gill clefts. x 20 
diams. 
PLATE III.—Pig Embryo of 12.0 mm. Reconstruction from transverse sec- 
tions, Series 5 and 518. 
For the most part the organs represented are in or near the median 
plane. The drawing illustrates especially the alimentary tract, the arterial 
system, and the heart. A. bas, Basilar artery. A. cau, Caudal artery. All, 
Allantois. Ao, Median dorsal aorta. Ao. d, Ao. D, Right dorsal aorta. A. 8, 
Subclavian artery. Au, Left auricle. A. wm, Umbilical artery. A. vi, Vitel- 
line artery (Omphalo-mesenteric). ¢, Coeliac axis. car. e, External carotid 
artery. car. i, Internal carotid artery. Cdl, Cerebellum. cl, Cloaca. cl. 
mem, Cloacal membrane. d, Left duct of Cuvier. Dien, Diencephalon. D. JV, 
Ductus venosus Arantii. ep, Epithelial plug in the rectum. Epgl, Epiglottis. 
f, interventricular foramen opening into the space a, b, ec, of Pl. 4. Fm, 
Foramen of Monro. f, 0, Foramen ovale. g, Gall-bladder. Jn, Entodermal 
wall of the intestine. is, An intersegmental artery. Mi, Renal pelvis. Lar, 
Larynx, Li, Liver. Lu, Lung. M. 6, Mid-brain. Md. 0b, Medulla oblangata. 
N, A spinal nerve. Neu, Neuromeres. Oe, Oesophagus. op, Optie stalk. P. 
A, Pulmonary artery. Pan, Dorsal anlage of the pancreas, behind the duct 
oe 
