EXPLANATION OF PLATES. 



Plate 1. 



Tampsia lishopi Stephejison. Side view of the type group a little less than 

 half natural size, from the upper part of the Mendez shale on Las Flores 

 hacienda, 9J kilometers north of Manuel station, State of Tamaulipas, 

 Mexico. (E), shallow anterior siphonal channel, and the trace of a narrow 

 sinu.s along its bottom. (S), posterior siphonal channel. Cat. No. 32499, 

 U.S.N.M. Page 6. 

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