Studies in Paleopathology 



V)i 



by the American Museum of Natural His- 

 tory of New York City, by Walker Museum 

 of the University of Chicago, and by the Uni- 

 versity of Kansas Natural History Museum. 



made by the well-known petrographic meth- 

 ods so common in all geological labora- 

 tories. The diagnoses, where they are at- 

 tempted, are made from comparisons of the 



Fig. 20. The skeleton of Slrutbiomimus altus, a small dinosaur from the Belly 

 River series (Cretaceous), Red Deer River, Alberta, Canada, now regarded as of 

 approximately the same age as the Judith River series. The unique feature of 

 the skull is the total absence of teeth, with a size of skull one-third larger than 

 the ostrich and a length of body of about fifteen feet. The position of the skeleton 

 is decidedly that of the opisthotonos which may be regarded as an indication of 

 disease. (After Osborn). 



A beautiful specimen of an osteoma, the 

 only one known so far, on the vertebra of a 

 Kansas Cretaceous mosasaur, was given the 

 writer by Dr. J. M. Armstrong of St. Paul. 

 The writer expresses his obligations to the 

 gentlemen connected with the above-men- 

 tioned institutions and to Dr. Armstrong. 

 The methods used are a combination of 

 procedures in the various lines involved. 

 Microscopic sections, which can be made 

 thin enough for immersion lens study, are 



material with similar lesions in recent hu- 

 man material; but strict diagnosis has not 

 been attempted. We must have some name 

 for the lesions, so the terms used must be 

 regarded as suggestive rather than an ac- 

 curate statement of conditions. The inter- 

 pretation of the lesions in the fossil material 

 is a matter of experience with fossil remains. 

 The author feels that twelve years experi- 

 ence in the study of fossils should be suffi- 

 cient to avoid most of the usual pitfalls. 



