BAL^NA. 23 



of its opening. Knox considered that in the growth 

 of the whalebone this flap covered and prevented its 

 extrusion through the side of tlie mouth. Figure, 

 p. 22. Knox Collection, No. 54. 



4. Skeleton of the same f(£tus, which, though dried and 



somewhat shrivelled, forms a natural skeleton. The 

 length of the cranium is 8 inches, that of the spinal 

 column 18 inches, together 26 inches. The summit 

 of the cranium is imperfect, but ossification of the 

 base, side walls, and jaws has materially advanced. 

 The curvature of the spine has been preserved by 

 introducing a wooden rod, modelled, into the spinal 

 canal. The bodies and neural arches of the vertebras 

 show centres of ossification in the dried cartilage. 

 Knox gives the vertebral formula C^D^gLCdog = 48. 

 A partial ossification of the pectoral limbs has taken 

 place. The pair of pelvic bones are also partially 

 ossified. Knox Collection, No. 55. 



[Nos. 5 to 7, from the above foetus, preserved in spirit, 

 were in the Knox Museum, in the Catalogue of 

 which, pp. 22 and 28, it is stated that from sixty to 

 seventy dentar pulps were dissected in each jaw 

 on each side. Knox, in succession to G. St Hilaire 

 and Cuvier, described the rudimentary teeth in 

 B. tnysticetus and recognised that the dentar pulps 

 disappeared. He regarded the baleen as a modified 

 form of hair and cuticle belonging to the integu- 

 mentary system.] 



5. Teeth, rudimentary. Sixteen dentar pulps with gum 



from the alveolar border of the upper jaw. 



6. Teeth, rudimentary. Seven dentar pulps dissected out of 



the gum of the same foetus and fixed upon a tablet. A 

 white calcareous incrustation may be seen on the pulps. 



-%*MiM»***>^** 



t • t 



[The upper figure shows eleven dentar pulps and the 

 gum, the lower four pulps dissected out of the gum.] 

 7. Teeth, rudimentary. Twelve dentar pulps together with 

 gum from the border of the jaw. 



