134 Proceedivgs of Indiana Academy of Science 



club shape in outline, probably due to flattening- in fossilization. The 

 tip joints of the left second walking leg seem to be preserved but they 

 are in contact with the crushed left pedipalp and their outlines are 

 difficult to distinguish. Only the first two joints of the third and fourth 

 paiis of walking legs are preserved. The coxae of the third pair seem 

 to be situated a little more anterior than the coxae in E. holti although 

 all the coxae resemble E. holti more than E. rakovnicensis. The basal 

 joints cf the fourth pair of legs abut against the genital operculum. 

 These are the skeletal plates referred to by Pocock, about whose func- 

 tion he was in doubt. The Indiana specimen clearly shows that these 

 belong to the fourth walking legs. 



One pectine is very well preserved and the other one very faintly. 

 Its structure as well as its plate of attachment is essentially similar to 

 that in E. holti. The plate of attachment is roughly pentagonal in out- 

 line. 



No trace of the stigmata has been detected. 



General Observations and Comparisons. This specimen is better 

 preserved than either of the other two specimens assigned to the genus. 

 It exhibits all features except the dorsal surface and the extreme tips 

 of the walking legs. Its closest relation is with E. holti (PI. I, figs. 4 and 

 b) rather than with the genotype, but it differs from the single known 

 fragmentary specimen E. holti in the shape of the praeabdomen and the 

 position of the coxae, with also the probable difference in the ratio of the 

 size of the sternum. It diffei's from E. rakovnicencis (PI. I, figs. 1 and 

 2), the genotype, in the shape and length of the pedipalpi, and in the 

 shape of the coxae and pectine. The absence of stigmata and the struc- 

 ture of the sternites suggests that these forms were not aii-breathers but 

 possessed respiratory organs similar to Limulus. 



