34 



HAY. 



EXPLANATION OF PLATE IL 



Fig. I, View of two eggs, containing young and showing the connecting cords. 



Fig. 2. View of the young taken from the egg, and enlarged to twice the natural 

 size. 



Fig. 3. View of the cartilaginous skull of the larva, as seen from above. Enlarged 

 10 diameters. 



Fig. 4. Same skull seen from side. Enlarged as Fig. 3. 



Fig. 5. Hyobranchial apparatus. Enlarged 10 diameters. 



Fig. 6. Transverse section across the snout of the larva. Enlarged 56 diameters. 



Fig. 7. Section across the snout of the larger specimen, six inches long. This is 

 designed to show the relations of the descending processes of the frontal bone to the 

 olfactory nerves. The nerve is seen, on the left side, passing through the descending 

 process. One branch is passing outward to the walls of the olfactory organ. The 

 section is cut somewhat obliquely, so that on the right side the olfactory nerve yet 

 lies mesiad of the descending process. Enlarged 32 diameters. 



Fig. 8. Section taken y'o'^ts of ^" i'^^h anterior to the preceding. Both nerves 

 have passed through the frontals, but the processes continue on with little change. 

 Enlarged 32 diameters. 



Fig. 9. Section across head of same individual as the last. Passes through the 

 foramen for the facial nerve. This figure illustrates the ossification of the columella, 

 and the broad process of bone that arises from it and passes up between the squa- 

 mosal and the prootic. The ceratohyal ossification lying between the two portions of 

 cartilage is seen, as well as the ossification of the first ceratobranchial. Increased 32 

 diameters. 



Fig. 10. Section through same skull and with the same enlargement. It passes 

 through the anterior edge of the stapes. Shows more especially the columella, car- 

 tilaginous at this point, the facial nerve passing below it, the posterior extremity of 

 the columellar process of the quadrate, and the passage of a portion of the saccular 

 branch of the eighth^ nerve into the labyrinth, and the large otolith. 



Figs. 5, 6, 7, 8, 9, and 10 were outlined under the camera and the details filled 

 in from the slide under higher power. Figs. 3 and 4 were partly drawn under the 

 camera and partly reconstructed from the sections. 



