SYSTEMATIC DESCRIPTIONS CENTRECHINOIDA. 23 



de Mao, Dominican Republic, T. W. Vaughan and C. W. Cooke 

 collectors, U. S. Geol. Sur. station 8519. 



Cidaris tribuloides (Lamarck). 



(Plate 1, Figures 18 to 20.) 

 Cidariles tribuloides Lamarck, 1816, Anim. sans Vert., vol. 3, p. 56. 



The following is a description of this species : 



Test moderate-sized, circular, ambulacra flush, very narrow; pores in 

 ambulacral plates crowded; interporiferous areas narrow with crowded 

 tubercles. Interambulacral plates with prominent tubercles and very 

 large areolae; space around scrobicules densely packed with small tuber- 

 cles. Diameter of peristome much greater than that of the apical disk. 



This Recent species, which is abundant in the living fauna of the 

 West Indies, has not been previously recorded as occurring fossil in 

 that region. Two finely preserved tests in the U. S. National Museum 

 are clearly referable to the species. The larger of the two measures 

 17 mm. in height, 29 mm. in diameter; width of ambulacrum at 

 the mid-zone 4 mm. ; width of interambulacrum at the mid-zone 13 mm. 

 The diameter of the periproct is 1 1 mm. and the diameter of the peris- 

 tome is 14 mm. There are 6 or 7 plates in each interambulacral 

 column, and the same is true of the smaller specimen. 



Cidaris tribuloides is close to C. melitensis, but differs from that 

 species as there described, the main features of difference being the 

 narrow ambulacra, crowded ambulacral pores, and the greater diameter 

 of peristome than apical disk in tribuloides. This species occurred 

 in the same lot with Echinometra prisca and Echinoneus cyclostomus, 

 both of which are found in the Oligocene of Anguilla, all as stated 

 under those species. 



Miocene (?), Santiago de Cuba, received January 29, 1910, 2 com- 

 plete tests and 3 fragmentary tests, U. S. Geol. Sur. station 5255, 

 U. S. Nat. Mus. No. 328221. 



Order CENTRECHINOIDA Jackson, 1912. 

 Suborder AULODONTA Jackson, 1912. 



Family PEDINID^E Gregory, 1900. 

 Genus ECHINOPEDINA Cotteau, 1866. 



Type species. Echinopsis gacheti Agassiz, 1846, Catalogue Raisonne, 

 Ann. Sci. Nat., ser. 3, vol. 6, p. 355. 



Echinopedina cubensis Cotteau. 

 (Plate 2, Figure 1.) 



Echinopedina cubensis Cotteau, 1881, Annal. Soc. Geol. de Belgique, vol. 9, p. 9, plate 1, 

 figs. 1 to 6; 1897, Bol. Com. Mapa Geol. Espana, vol. 22, p. 16, plate 2, figs. 1 to 6. 



Regular Echini other than the Cidaroida appear to be extremely 

 rare as fossils in the West Indies, while a few have been described 



