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THE AMERICAN NATURALIST [Vol. LIT 



brates assume the pleurothotonic attitude, since often 

 the ganoid fishes (Fig. 6), especially, assume the opistho- 

 tonos. It is true that the majority of fishes which are 

 preserved in an approximately complete manner exhibit 

 no trace of either of these attitudes. The great series of 

 Triassic fishes from Connecticut seldom exhibit indica- 



tions of either of these phenomena. A single specimen of 

 ( 'afopfmis gracilis, of those figured by Eastman, 5 exhibits 

 tlie opisthotonos, and a single one. Ptychnlepis marshi, 

 exhibits pleurothotonos. Of the scores of specimens of 

 these fishes described h\ Xewberry and Eastman a very 

 small percentage show any sign of spastic distress. 



As a clinical manifestation of great severity, opistho- 

 tonos and the correlative phenomena, pleurothotonos and 

 emprosthotonos (opisthotonos), have long been well 

 known m human beings as accompanying certain phases 

 of tetanus, abscesses of the brain, otitis media, hysteria, 

 cerebrospinal meningitis, strychnine poisoning, and other 

 afflictions, in which toxins affecting the nervous system 

 are liberated. In these manifestations the muscles of the 

 body, the spine and the extremities are stronglv flexed. 

 This characteristic attitude of the spasm has been graph- 

 ically figured (Fig. 7) by Sir Charles Bell in his "Anato- 

 my of tfhe Expressions," where he says : 



that all the muscles are rigidly contracted, the more ' powerful flexors 



