156 JOHN BEARD. 
in all five clefts. This figure isa more diagrammatic view of Fig. 51, which 
represents nature more or less accurately. 
Fie. 47.—Horizontal section of a Torpedo embryo, showing rudiment (c/. v1) 
of a sixth true branchial cleft. 
Fic. 48.—Low power drawing of transverse section through nose of an 
adult Triton, showing Blaue’s smell-buds (sm. 0.). 
Fie. 49.—High power drawing of two such smell-buds. Z. ¥, oc. 2, 
cam. lue. 
Fic. 50.—Diagrammatic transverse section through the gill-bearing region 
of an Hlasmobranch or other Ichthyopsid. Nervous system not yet closed in. 
On the left side the gill muscle plate is shown, and on the right the gill-cleft. 
h.c. Head-cavity. 2. s. Nervous system. yp. 7. Posterior root. 2. Noto- 
chord. jp. dr. o. Branchial sense organ. Or. gl. Branchial ganglion. J. m. 
Lateral muscle plate. yp. z. Postbranchial nerve. a/.c. Alimentary canal. 
Fic. 5].—Diagram taken partly from my own drawings and partly from Dr. 
Marshall’s. Shows the ganglia and various branches of the cranial nerves. 
Also mouth (m.) and gill-clefts (c/.,, c/.,), &c. For lettering see general list. 
