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5 
Fig. 
oO Or He OF b 
OF THE SKULL IN SHARKS AND SKATES. 233 
. Another embryo, 11 lines long, seen as an opaque object, x 14 diam. 
The same, seen from below, x 14 diam. 
. The same, seen from above, x 14 diam. 
. The same, in longitudinal section, x 14 diam. 
. Part of fig. 1, x 24 diam. 
PLATE XXXV. 
. First stage. Side view of Pristiurus embryo, } of an inch long, x 20 diam. 
. The same, from below, « 20 diam. 
. Dissection, from above, of the same embryo, x 20 diam. 
. Dissection, from above, of a larger embryo (# of an inch long), x 20 diam. 
. Dissection, from above, of an embryo of Seylliwm canicula (13 lines long), 
x 20 diam. 
. Second stage. Dissection, from above, of a larger embryo of Seylliwn canicula 
1j inch long, x 14 diam. 
. The same, dissected from below, * 14 diam. 
. Part of fig. 6, x 30 diam. 
PLATE XXXVI. 
. Second stage. Side view of head of Scylliwm canicula, partly dissected, from 
an embryo, | inch 2 lines long, x 12 diam. 
. Vertical section of a somewhat larger embryo, x 14 diam. 
. Third stage. Chondrocranium of a two-thirds-ripe embryo of the same fish, 
1 inch 8 lines long, seen from above, x 10 diam. 
. The same object, seen from below, x 10 diam. 
. The cranium without the facial arches; side view, x 10 diam. 
6. Section of head of the same, x 14 diam. 
PLATE XXXVII. 
. Third stage, continued. Skull of the same, seen from below, x 10 diam. 
. Fourth stage. Adult Dog-fish, upper view of the skull, x 14 diam. 
. The same, with facial arches removed, under view, X 12 diam. 
. Section of head of the same, x 13 diam. 
. Part of same object, x 53 diam. 
PLATE XXXVIII. 
. Skull of adult Dog-fish, seen from below, x 13 diam. 
. Side view of same, x 14 diam. 
. End view of same, x 13 diam. 
. Vertieal section of cranium, x 14 diam. 
