144 
ME. W. K. PAEKEE ON THE STEUCTUEE AND 
PLATE IV. 
Fifth Stage. — “Fry” the second week after hatching . 
Fig. 1. Side view of primordial skull. x24 diameters. 
Fig. 2. Upper view of same. X 24 diameters. 
Fig. 3. Lower view of same. X24 diameters. 
Fig. 4. Vertical section of the head. X 24 diameters. 
Fig. 5. Part of same section. X 48 diameters. 
Fig. 6. Another vertical section (part) a little to the right. X24 diameters. 
Fig. 7. Section through the eyes [of fourth stage). X25 diameters. 
PLATE V. 
Sixth Stage. — Young Salmon of the sixth week after hatching. 
Fig. 1. Transverse section through anterior part of auditory capsule. x20 diameters. 
Fig. 2. Section of head (vertical). X 16^ diameters. 
Fig. 3. Transverse section through nasal sacs. X 20 diameters. 
Fig. 4. A similar section through fore part of orbit, x 20 diameters. 
Fig. 5. Section through ear-sac {fifth stage). X 20 diameters. 
Seventh Stage. — Young Salmon of the first summer , 1|- to 2 J inches long. 
Fig. 6. Vertical section of head. X 15 diameters. 
Fig. 7. Side view of skull. Xl5 diameters. 
Fig. 8. Facial bars of same. Xl5 diameters. 
Fig. 9. Lower view of face. X 20 diameters. 
Fig. 10. Section of fore part of skull. X 15 diameters. 
PLATE VI. 
Eighth Stage. — Adult Salmon. 
Fig. 1. Side view of skull and face. Nat. size. 
Fig. 2. Same, with outer bones removed. Nat. size. 
Fig. 3. First branchial arch. Nat. size. 
Fig. 4. Second branchial arch (part). Nat. size. 
Fig. 5. Lateral view of basibranchiostegal. Nat. size. 
PLATE VIE 
Eighth Stage (continued). 
Fig. 1. Upper view of skull with bony plates on. Nat. size. 
Fig. 2. The same, from below. Nat. size. 
