38 SPECIMENS OF CETACEA. 



37. Aorta. Transverse section of the abdominal aorta of the 



Rorqual 35 feet long ; the diameter of the lumen is 

 4 inches. 



38. Lymphatic trunks, three in number, converging to join 



the thoracic duct. They are inverted to show the 

 lining membrane and the semilunar valves. 



39. Lymphatic trunk, inverted, from the lower part of the 



abdomen of the same Rorqual ; the lumen is more 

 than half an inch in diameter. 



40. Skin. Section from the skin of the back of the same, 



showing the subjacent blubber. 



41. Skin. Section of cutis vera of the same Rorqual. The 



cuticle has been removed and the closely set papillge 

 of the cutis are exposed. The papillse rest upon the 

 dense fibrous structure of the cutis. 



42. Skin. Horizontal section of dorsal fin of Rorqual. In 



the middle of the section is the cutis vera, from which 

 the papillae project into the thick cuticle. 



43. Skin. Perpendicular transverse section showing a similar 



structure. 



44. Skin. Transverse horizontal section of the anterior 



margin of the dorsal fin of the same animal, showing 

 similar structure. 



4.5. Skin. Section through the caudal fin of a Rorqual, B. 

 musculus, showing the dense fibrous structure of the 

 cutis vera. 



4(j. Skin. Cuticle of a Rorqual, probably B. 'musculus, show- 

 ing the rich black colour of the deep surface. 



47. Skin. Cuticle of the abdomen of the same Rorqual, 



showing its grey colour mottled with brown spots. 



48. Skin. Superficial part of the cuticle of the same Rorqual, 



feebly pigmented. 



49. Skin. Portion of cuticle of a Whale, species not named. 



It consists of two layers not strongly pigmented, and 

 extending through it is a white band, probably a 

 cicatrix. 



50. Eyeball of a large Rorqual in antero-posterior section 



through the optic nerve and the vascular connective 

 tissue which surrounds it. The retina is seen lining 

 the chamber for the vitreous humour. The great 

 thickness of the sclerotic behind and its decrease in 

 front are exhibited. 



