392 



Annals of Medical History 



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Fig. 19. Microscopic section of one of the lesions 

 from the surface of the humerus, Fig. IS, showing 

 bundles of perforating fibers of Sharper, osseous 

 lacunae, and vascular openings. The large clear 

 space at the upper portion of the picture is a vascu- 

 lar opening filled with calcite crystals. 300 diameters. 



A similiar condition is seen in the skeleton 

 of a Triassic nothosaur. We are not justified 

 in stating on these evidences the presence of 

 pituitary disturbances in ancient animals, 

 but further studies in this line may add 

 very interesting data. 



1 2. Osteoperiostitis or some similar dis- 

 turbance is the result seen in the arm bones 

 of a mosasaur from the Cretaceous of 

 Kansas (Fig. 18). The articular surfaces 

 are very greatly roughened and the surfaces 

 of the bones are covered with smooth, 

 somewhat flattened excrescences, possibly 

 due to a subperiosteal irritation. The lesions 

 have been observed in no other instances, 

 so that no comparative statements can be 

 made. Microscopic study of the peripheral 

 lesions reveals many interesting histological 

 details. One area shows typical osteoid tis- 

 sue, similar in all essential respects to 



36 This subject has been discussed at length by 

 the writer, in "Opisthotonos and Allied Phenomena 

 among Fossil Vertebrates," American Naturalist, 

 1918. 



osteoid tissue developed in a human humer- 

 us in a case of osteomyelitis. Other areas, 

 such as the one figured (Fig. 19), show per- 

 forating fibers of Sharpey, as seen in the 

 dark bundles, and the nature of the osseous 

 Iacunse. The whole section is filled with 

 vascular spaces. An especially large one, 

 filled with calcite crystals, is seen in the 

 upper portion of the picture. There are no 

 apparent Haversian systems or canals. 

 \\ hether this is due to the pathology of the 

 bone or whether it is an occurrence in nor- 

 mal bone of the mosasaurs will be deter- 

 mined later by microscopic study of the 

 normal tissues. 



13. Opisthotonos and the allied phe- 

 nomena, pleurothotonos and emprostho- 

 tonos, are quite frequently seen among 

 fossil vertebrates. It has been suggested 

 elsewhere that these attitudes represent 

 possible cerebrospinal infections or other 

 neurotoxic conditions, and they must be 

 considered in connection with the study 

 ol disease among fossil animals. 36 The skele- 

 ton of the small dinosaur, Strut hiomimus 

 altus (Fig. 20), described by Osborn, 37 

 shows a very well-developed condition of 

 opisthotonos, with the head thrown sharply 

 back, the tail strongly flexed, and the toes 

 contracted and appressed. The whole atti- 

 tude strongly suggests a spastic distress, 

 possibly brought on by some form of 

 poisoning of the central nervous system, 

 from infection or the deglutition of some 

 poisonous substance. 



14. Osteomalacia is evidently the cause 

 of the hypertrophy of the bones of Lim- 

 nocyon poteris, an early carnivore from the 

 Washakie Eocene of Wyoming, nearly 

 3,000,000 years old. 



materials and methods 



The material described in the present 

 paper has been loaned the writer for de- 

 scription by the Field Museum of Chicago, 



"Osborn: Bull. Amer. Mus. Natl. Hist., I9i7> 

 vol. 35, p. 733. pl- 28. 



