234 MB. W. K. PAEKEK ON THE SKULL IN SHARKS AND SKATES. 



PLATE XXXIX. 



Fig. 1. Skate. First stage. Side view of embryo of Raia maculata, 1 inch 4 lines 



long, 7 weeks old, from the deposit of the egg-pouch, X 14 diam. 

 Fig. 2. Same object, with facial arches shown, X 14 diam. 

 Fig. 3. Part of same, X 20 diam. 

 Fig. 4. Under view of same embryo, X 14 diam. 

 Fig. 5. Upper view of same, X 14 diam. 

 Fig. 6. Part of fig. 5, Plate XXXV., Scijllium, X 40 diam. 



PLATE XL. 



Fig. 1. Second stage. Under view of fore part of an embryo of Raia maculata, 



3 months from deposit of egg-pouch, X 3| diam. 

 Fig. 2. Upper view of same, X 3| diam. 

 Fig. 3. Side view of same, X 7 diam. 

 Fig. 4. Skull of same, seen from above, X 5 diam. 

 Fig. 5. Same object, seen from below, X 5 diam. 

 Fig. 6. Cranium of same, from below, X 5 diam. 

 Fig. 7. Part of fig. 3, Plate XXXV. X 40 diam. 



PLATE XLI. 



Fig. 1. Third stage. Section of cranium of Baia clavata (nearly ripe embryo), 



X 7 diam. 

 Fig. 2. Transverse section of same through nasal sacs, X 14 diam. 

 Fig. 3. Fourth stage. Skull of adult i?«za c/aua/a, from above, X IJ diam. 

 Fig. 4. The same, side view, X 1 J diam. 

 Fig. 5. Hyoid arch, with " branchial rays " of same, inner view, X 1^ diam. 



PLATE XLII. 



Fig. 1. Third stage, continued. Section through antorbital region of ripe embryo of 



Raia clavata, X 14 diam. 

 Fig. 2. A similar section of same, through the eyes, X 14 diam. 

 Fig. 8. Another section through auditory sacs, X 14 diam. 



Fig. 4. Fourth .ifage continued. Under view of skull of adult Raia clavata, X 1^ diam. 

 Fig. 5. Transverse section of skull of Dog-fish, 3rd stage, through the eyeballs, x 14 diam. 

 Fig. 6. Another section, rather oblique, in postorbital region, X 14 diam. 

 Fig. 7. A third section, through the auditory capsule, X 14 diam. 



