36 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I45 



U.S.N.M. 648169, loc. 7; U.S.N.M. 648170, 648171, 648172, loc. 4; 

 U.S.N.M. 648168, loc. 6. 



ENCOPE TAMIAMIENSIS Mansfield 

 Plate 14, figures 1-6; text figures 31-35 



Encope macrophora (Ravenel) (part), Clark and Twitchell, 1915, U. S. Geol. 



Surv. Mon. 54, p. 206, pi. 94, figs. la-f. 

 Encope macrophora tamiamiensis Mansfield, 1932, U. S. Geol. Surv. Prof. 



Paper 170-D, p. 48, pi. 17, fig. 8. 

 Encope michelini Agassiz. Barry, 1941, Proc. U.S. Nat. Mus., vol. 90, pi. 65, 



fig. 4. 

 Encope tamiamiensis Mansfield. Cooke, 1942, Journ. Paleont., vol. 16, no. 1, 



p. 20 

 Encope tamiamiensis Mansfield. Cooke, 1959, U. S. Geol. Surv. Prof. Paper 321, 



p. 48, pi. 17, figs. 3, 4. 



Diagnosis. — Species characterized by thin margin, smaller lunule, 

 and more posterior apical system. 



Material. — More than 1,000 specimens. 



Shape. — Length varying from 7.6 to 122 mm; width varying 

 from slightly wider than high to 80 percent of length, with average 

 specimen slightly narrower than long (text fig. 31) ; marginal outline 

 subcircular, truncated posteriorly; five ambulacral notches; anterior 

 notch slight, posterior notches deep; on smallest specimens no 

 notches ; posterior notch well developed, present on all specimens, 

 elongate, irregular in shape and size; test low, height varying from 

 10 to 20 percent with an average of 14 percent of the length (text 

 fig. 32), greatest height posterior of center at anterior edge of lu- 

 nule ; margin very sharp with test thin at margin ; adoral surface 

 evenly concave. 



Apical system. — Anterior (text fig. 33) distance from anterior 

 margin to apical system approximately 40 percent of length of test ; 

 large central star-shaped madreporite with five genital pores, genital 

 pore 5 usually eccentric to right (pi. 14, fig. 5). 



Ambulacra. — Anterior petals II, III, IV lanceolate, straight, of 

 approximately equal length, with interporiferous zones wider, equal 

 to or narrower than poriferous zones ; posterior petals V and I longer, 

 curving posteriorly, interporiferous zones narower than poriferous. 

 In specimen 75 mm long 70 pore-pairs in each poriferous zone in 

 petal III ; 62 in petals II or IV ; 80 in petals V or I ; rate of intro- 

 duction of new pore-pairs decreases with growth (text fig. 34.). 



Periproct. — Opening small, elongate, located at anterior edge of 

 lunule at inner margin of first pair of postbasicoronal plates in most 

 specimens, in several not in lunule but anterior to it. 



