No. 2218. FOSSIL ECUIA'I OF PANAMA CANAL ZONE— JACKSON. 491 

 CLYPEASTER GATUNI, new species. 



Plate 63, fig. 1, plate 64, fig. 1. 



This species is represented by a fine, large specimen in perfect con- 

 dition of preservation. Two additional specimens much worn and 

 incomplete are also referred to it. 



The type measures 146 mm. in length, 122 mm. in width, and 35 

 mm. in height. The test is elongate, moderately pentagonal in out- 

 line, with slight incurving of the borders in intcrambulacral areas 

 1, 2, 3, and 4. Its greatest width is across ambulacra II and IV. 

 Ventrally the test is deeply concave, being flat only on the border. 

 The ambulacral petal III is equal in length to petals I and V and 

 a few millimeters longer than are petals II and IV. The petals are 

 equidistant, highly elevated, and open at their distal ends. Ventrally, 

 five deep ambulacral grooves extend to the mouth. Interambu- 

 lacra are broad on the border of the test, narrowing up dorsally and 

 very narrow near the apical disk. Each of the intcrambulacra 

 between the petals are strongly elevated as if pinched up. The 

 apical disk is slightly anterior to the middle of the test anH is very 

 small. The mouth is central, deeply sunken. The periproct is 

 ventral, slightly elliptical, its posterior border 5 mm. from the 

 posterior limits of the test. Tubercles are small, covering the 

 dorsal surface of the test, ventrally the same, but slightly larger. 



Clypeaster gatuni approaches nearest, perhaps, to C. howersi Weaver, 

 but differs in the shape of the test, the deeply concave base, the 

 shape and proportionate size of the petals and intcrambulacra dor- 

 sally, and the fact that the periproct is ventral instead of terminal. 



Locality and geologic occurrence. — Gatun formation, upper Oli- 

 gocene or Miocene. Panama Canal Zone, near Gatun Dam site, 

 D. F. MacDonald, collector, 1911, holotypo, U. S. National Museum, 

 station No. 5662, one specimen. 



Limestone in swamp, north of Ancon Hill, about 4 miles south of 

 Diablo Ridge in the Emperador limestone, U. S. National Museum, 

 station No. 6237, two specimens. 



Holotype.— Cat. No. 324453, U.S.N.M. 



This species is present on both the Atlantic and Pacific sides of the 

 Isthmus. 



ENCOPE ANNECTANS. new spectea. 



Plate 65, figs. 1, 2; plate 66, fig. 1. 



This interesting new soecies is represented by three specimens 

 which include two tests free from matrix and more or less complete, 

 and a sandstone mold of the exterior of the ventral side of a specimen 

 which is the largest of the three. 



In shape, the specimens arc thin, flattened, and nearly circular in 

 outline, excepting for the reentrant marginal ambulacral notches. 



