238 



M. Pt. — Meta-pterygoid. 



m. r. u. — Macula acustica recessus utriculi. 



Ms. Pt. — Meso-pterygoid. 



Mx. — Maxilla. 



mx. V. — R. maxillaris trigemini. 



N. — Cup shaped cavity at each end of centrum containing vestiges of the 

 notochord. 



N. A. — Neural arch. 



Nc . —Notochord . 



N. C. — Notochordal canal in centrum placing the notochordal spaces (N.) 

 in communication. 



n. ch. I 



, , y — Right and left nasal chambers. 

 n.cii.^ 



n. olf. I 



i — Right and left olfactory nerves. 



N. S. — Neural spines, numbered from before backwards. 



N. S.j — Last three neural spines. 



n. sac.^-^ — The five right and left nasal sacs. 



n. sp.' I 



- — NN. splanchnici. 

 11. sp.' [ 



O.C. — Occipital condyle. 



Oc. S. — Occipital spine. 



Od. — Opening of oviduct. 



Od.' — Common ovarial chamber. 



Od." — Interior of right ovary. 



o. i. — Branch of the N. oculomotorius to the inferior oblique muscle. 



o. lam. 



, -Right and left series of olfactory laminae. 

 0. lam.' ' 



0/J. — Operculum. 



Op. 0. — Opisthotic. 



o. ly)-. — Nervvis ophthalmicus profundus (trigemini ?) and ganglion. 



op. s. vii. — R. opercularis superficialis facialis. 



o. s. — N. patheticus to superior oblique muscle. 



oto. — Saccular otolith. 



out. buc. — R. buccalis externus facialis. 



Pa.— Palatine. 



pal. — R. palatinus facialis. 



J), a. I. — Papilla acustica lagense. 



Pa. P. — Parotic process of pterotic and opisthotic. 



