NOS. 620-621] STUDIES IN PALEOPATHOLOGY 



393 



AUitjatorium Meyeri (PI. X), two specimens of AUiga- 

 torellus Beaumonti (PI. XI), and Crocodileimus robustus 

 (PI. IX), exhibit any decree of the opisthotonic attitude. 

 Only one, Pleurosaurus Goldfussi (PL VII), exhibits the 

 pleurothotonos. The majority of the remaining- skeletons 

 ligurod show no spastic distress wliatever. So that while 

 we may say that these two positions are common they are 

 rather the unusual than the usual state of affairs. 



On the other hand the dinosaurs Stnithioniinnts altus 

 and Compsognathus longipes, many specimens of small 

 pterodactyls and the fossil bird A rchmptrni < exhibit 

 such a marked opisthotonic attitude as to lead one to infer 

 some cerebral-spinal or other intracranial infection which 

 would have been easily possible in the poorly protected 

 brain case of these early vertebrates. It requires but a 

 glance at the nature of the brain case of the early verte- 

 brates to see how poorly protected the cerebrospinal 

 spaces were. Ingress of infecting bacteria may have been 

 through any of the numerous nerve or vascular foramina, 

 through the thin cancellous walls separating the brain 

 case from the sphenoidal sinus, and through the anterior 

 end of the brain case which was often protected only by a 

 membranous covering, by cartilage, or by very thin bony 

 plates. 



The possible presence of the infecting bacteria has been 

 so well established by the investigations of Waleott.* van 

 Tieghem and Renault, 1 " that little need be said here 

 concerning them. Walcott has described and figured bac- 

 teria from fossilized Pre-cambrian alga- of central Mon- 



