Studies in Paleopathology 



389 



early geological periods so closely resemble 

 the lesions of today. Section of the tumor 

 mass shows the presence of numerous vascu- 

 lar spaces, so that in this respect it re- 

 sembles a hemangioma. Microscopic study 

 of the periphery (Fig. 16) shows the pres- 

 ence of well-developed Haversian systems 

 of osseous lamellae. 



Fig. 15. Outline sketch showing normal appear- 

 ance of the two vertebra?, based on Diplodocus and 

 Apa osaurus. A = chevron. This process in the 

 pathological specimen has been hoved far ventral- 

 ward and involved in the tumor-like mass. 



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Fig 16. This figure will show the possibilities in 

 the microscopic study of fossil bones. The drawing, 

 300 diameters, shows the osseous lacunae, with short 

 canaliculi arranged around a large vascular opening, 

 thus simulating an Haversian system. The lacunae 

 of dinosaur bones are much smaller than are the 

 lacunae in other extinct forms. The dark areas 

 are due to the staining of iron with which the 

 bones are nfilt rated. The section was taken from 

 the per phery of the specimen shown in Fig. 14. 



The bones exhibiting these interesting 

 indications of Mesozoic pathology are the 

 caudal vertebrae of a huge land reptile, one 

 of the sauropodous dinosaurs, possibly Apa- 

 tosaurus. The position of these bones in the 

 body of the animal is indicated by the 

 arrow in Fig. 17. The sauropodous dino- 

 saurs were the most gigantic of all land 

 vertebrates, although not nearly so large 

 as some of the modern whales. The largest 

 of these reptiles attained a length of nearly 

 70 feet and an estimated weight of 39 tons. 

 The head was approximately the size of 

 that of a modern draft horse and the con- 

 tained brain was no larger than one's fist. 

 The lumbar intumescence, however, was ten 

 times the size of the cephalic portion of the 

 nervous system, or at least the subdural space 

 was. Whether the nervous material filled 

 the entire cavity or not is unknown. The 

 animals lived, possibly, in the swamps and 

 low-lying rivers, feeding on the succulent 



vegetation, and are said to have been ca- 

 pable of attaining the ripe age of 1,000 years. 

 Diseases are rarely seen on fossil dinosaur 

 bones, in spite of the great abundance of 

 their remains. 



The tail in some of these large animals was 

 very long and slender, and it may have 

 been used in swimming, as a muskrat uses 

 his today. The terminal caudals in some 

 species were reduced to mere slender rods 

 of bone, so that a fracture or an injury of 



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Fig. 17. Outline figure with skeleton, of Bron- 

 tosaurus, showing at the arrow the location of the 

 vertebrae shown in Fig. 14. This animal attained a 

 length of near y 70 feet, a height of 1 5 feet and a 

 weight of many tons. (Based on a figu e by Mat- 

 thew.) 



