GEOLOGY AND PALEONTOLOGY OP THE CANAL ZONE. 



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central in position, the periproct is elongate oval, its anterior border 

 is 13 mm. posterior to the border of the mouth opening. Poste- 

 riorly the periproct is confluent with the infolded depression of the 

 interambulacral lunule. 



The ambulacral petals are rather narrow in this specimen, measur- 

 ing 13 mm. in width. The odd anterior ambulacral petal is longer 

 than the others, and measures 36 mm. in length, whereas the pos- 

 terior petals of the trivium measure 28 mm. in length. The petals 

 of the bivium, or I and V, are longer than the posterior pair of the 





v 



Fig. 2. — Bncope platxtata. Drawing op the type-spec imen, natural size. RESTORA- 

 TIONS ARE INDICATED BY DOTTED LINES. 



trivium, but as they are incomplete posteriorly, a measurement can 

 not be given. On the ventral side, the ambulacral furrows are 

 strongly marked and each gives off a few weakly impressed branches. 

 The apical disk is quite well preserved, shows clearly the ocular 

 pores and four of the five genital pores, which are a characteristic 

 feature of Encope. The only genital pore wanting is that occurring 

 in area 1, which is destroyed by a local fracture of the test. Minute 

 tubercles cover the dorsal side of the test. Ventrally the tubercles 

 are larger except near the ambulacral furrows where they are minute.. 



