500 PROCEEDINOS OF THE NATIONAL MUSEUM. vol.63. 



SCHIZASTER PANAMENSIS. new species. 



Plate 66, figa. 2-3. 



The material consists of an internal mould free from matrix, and 

 three specimens more or less complete, embedded in porous, dark- 

 colored volcanic tuff which also bears some fragments of lignite. 

 The specimen, free from matrix, is the most completely preserved, 

 although somewhat compressed dorso-ventrally, and is selected as 

 the type. The specimen measures 48 mm. in length, 40 mm. in width, 

 and 25 mm. in height. The petals of the ambulacra are situated in 

 broad, deep furrows. The anterior petal III extends to the anterior 

 limit of the test and measures 23 mm. in length. The paired anterior 

 ambulacra II and IV are in grooves 13 mm. long and diverge widely 

 from the anterior petal. The posterior petals I and V are shorter 

 than the anterior pair, measuring 5 mm. in length, and are directed 

 almost straight baclvward. The position of the periproct is not 

 clearly indicated on the mould, but apparently it is near the upper 

 part of the posterior face. The peristome is wide and rounded, and 

 is situated 16 mm. from the anterior border of the test. The peri- 

 petalous fasciole is quite wide and is fairly well shown in areas II 

 and IV on the type-specimen and still better in one of the fragments, 

 which is a counterpart of the dorsal side of the same. 



One of the specimens, which is an external mould, shows the impress 

 of the outline of the plates of part of a test, and gives measurements 

 of considerable interest. It measures about 50 mm. in length, 

 about 45 mm. in width, and about 38 mm. in height. From incom- 

 pleteness of the specimen no exact measurements can be given, yet 

 those available indicate a very high test. 



Locality and geologic occurrence. — Gatun formation, upper Oligocene 

 or Miocene, Panama Canal Zone. Second cut, south of Gatun II. R. 

 Station, Goldman Coll., U, S. iNational Museum station No. 7294, four 

 specimens. Holotype, U. S. Nat. Mus. Cat. No. 324461. Another 

 specimen, imperfect and much worn, with a very high test, and appar- 

 ently referable to this species, is from Panama Canal Zone, Gatun, 

 section A, from middle of Bed " E," D. F. MacDonald, collector, U. S. 

 National Museum station No. 6008, one specimen. U. S. Nat. Mus. 

 Cat. No. 324462. 



DESCRIPTION OF PLATES. 



Plate 62. 



Fig. 1. Clijpeaster lanceolatus Cotteau, dorsal view, natural size. The dark spot in 

 interambulacrum 5 is a yellow label that took black in the photograph. 

 U. S. Nat. Mus., Cat. No. 324451, Station 5866&. 

 2. Another specimen of the same, ventral view, natural size, U. S. Nat. Mu3., 

 Cat. No. 324451, Station 58G6&. 



Plate 63. 



FiQ, 1. Clypeaster gatuni, new species, dorsal view. Holotype, slightly reduced, U. 

 S. Nat. Mus., Cat. No. 324453, Station 5662. 



