Bull. U. S. B. F. 1912. 
Plate LXI. 
pII.I, FILAMENTS OF 4 TH ARCH 
i HEAD OF KIDNEY 
; j ESOPHAGUS 
ORAL MEMBRANE 
OPERCULUM 
PREOPERCULUM 
CHEEK muscle IN SECTION 
1 ST BRANCHIAL ARCH 
4TH BRANCHIAL ARCH 
3Kn BRANCHIAL ARCH 
2 XD BRANCHIAL ARCH 
Fig. 15. — Composite picture of lateral and longfituditial distribution of normal thyroid in the Salmonidie. with vessels. 
auricle 
BULBUS aortae 
.VENTRICLE 
ORAL MEMBRANE 
TEETH OF TONGUE 
1ST COPULA (CARTILAGE) 
ST BASIBRANCHIAL 
2ND BASIBRANCHIAL 
RTILAGE; 
D COPULA (CARTILAGE) 
4TH BASIBRANCHIAL 
3RD BASIBRANCHIAL 
3RD COPULA (CARTILAGE) 
4—. VENOUS SINUS 
EAL MUCOSA 
TISSUE 
MUSCLE 
MUSCLE 
: : JUGULAR PIT 
BRANCHIAL SEPTUM 
SYMPHYSIS OF DENTARY 
i HYPOHYAL SYMPHYSIS 
MUSCLE : 
jp:pithelium 
.‘SUBMUCOSA 
SYMPHYSIS OF CLAVICLE— CORACOID PAIRS 
VENTRAL AORTA 
i UROHYAL 
BRANCHIAL SPACE 
BASI 
HYAL 
TONGUE 
Fig. 16. — Longitudinal and dorso-ventral distribution of thyroid in the Salmonidie. 
