BUFFALO SOCIETY OF NATURAL SCIENCES 



2 55 



From these figures it appears that the Kokomo forms had cephala 

 which were much more nearly square than rectangular. A set of 

 comparative figures for the proportions in the different parts of the 

 three species brings out the differences clearly. 



Lengths in millimeters 



SPECIES 



CARAPACE 



PREABDO- 



MEN 



POSTABDO- 



MEN 



TELSON 



RATIO OF CARA- 

 PACE TO REST 

 OF BODY 



E. dekayi 



E. ranilarva < 



E. kokomoensis 



3i 

 35 

 33 

 28 



4O.4 

 40.0 



43-5 

 3 2 -3 



56.O 

 50.0 



4i-5 

 43-4 



53-o 

 35° 

 36.0 



3° -4 



20.7 : 100 



27.8 : 100 

 27.0 : 100 



25.9 : 100 



The same relations hold here between the body proportions of the 

 Kokomo and Bertie species as held in the case of Eusarcus. A com- 

 parison of the figures for E. dekayi and the first specimen of E. 

 ranilarva shows that though the carapace of the latter is longer, all 

 of the other parts of the body are shorter. Thus, the Eurypterus 

 species as well as the one of Eusarcus are relatively shorter and 

 broader forms than the ones found in the Bertie. 



The Kokomo eurypterid fauna as a whole is quite distinct from 

 any other American fauna, a fact which is difficult to explain on the 

 theory of marine habitat for these organisms. If, as Clarke and 

 Ruedemann have stated, the Kokomo is of Lockport age, and belongs 

 to the marine fauna of that time, it is greatly to be wondered at that 

 there should be no eurypterid fauna in the succeeding Guelph beds 

 in the same locality or in adjoining regions. Yet the only Guelph 

 form that has ever been found is the single specimen of Eurypterus 

 (Tylofterus) boylei from Ontario, a form which shows not the slightest 

 resemblance to any of the Kokomo eurypterids. If the Kokomo is 

 to be considered of Monroan age, for reasons which have been given 

 in full on p. 118 then, on the marine theory, the Kokomo forms should 

 show relationship to the Bertie, and their area of deposition should 

 constitute merely another "pool" cut off from the Monroan sea. 

 But it has just been shown that the Kokomo fauna is quite distinct 

 from the Bertie and that the two faunas have no species in common, 

 a fact difficult to explain on the ground that the forms lived in neigh- 

 boring "pools" where faunas were segregated from a once wide- 

 spread marine fauna. 



