30 FOSSIL ECHINI OF THE WEST INDIES. 



Sismondia antillarum Cotteau. 



(Plate 2, Figures 6, 7.) 



Sismondia antillarum Cotteau, 1875, Kongl. Sven. Vet. Akad. Handl., vol. 13, No. 6, p. 17, 

 plate 3, figs. 1 to 4. 



The following is an extract from the original description of this 

 species : 



Species of small size, rounded, slightly pentagonal, a little angular anteri- 

 orly. Upper face nearly flat, thickened on the border, subdepressed around 

 ambulacral petals; apical disk central. Ambulacral petals short, narrow, 

 subcostulate, closed at the tips. Ambulacral pores very unequal, the internal 

 rounded, the outer narrowed, oblique, elongate. Beyond the petals the 

 pores are no longer visible, but reappear on the ventral side, though few 

 and rare. Tubercles of small size, numerous, crowded, homogeneous. 

 Periproct circular, nearer to the posterior border of the test than to the 

 peristome, which is not preserved in the single known specimen. 



The material in the U. S. National Museum consists of one quite 

 complete specimen, evidently the original of Cotteau's figures, and 

 a fragment, about one-half of a test. Cotteau says there is only one 

 specimen, so this second one may have come in later. The complete 

 specimen measures 3.25 mm. in height, 13.5 mm. in length, and 13 mm. 

 in width through ambulacra II and IV. These measurements are 

 slightly greater than those given by Cotteau, but in a number of 

 specimens measured I do not find that my measurements quite agree 

 with his. The specimen does not show the genital and ocular pores, 

 but a pit, dorsal to interambulacrum 2, appears to be the single madre- 

 poric pore which is characteristic of the genus. 



Eocene, St. Bartholomew limestone, St. Bartholomew, Guppy 

 collection ex Cleve, the holotype, the original of Cotteau's figures, and 

 an additional fragmentary specimen, U. S. Nat. Mus. No. 115394. 



Sismondia anguillae Cotteau. 



(Plate 2, Figures 8, 9.) 



Sismondia anguilla: Cotteau, 1875, Kongl. Sven. Vet. Akad. Handl., vol. 13, No. 6, p. 18, 



plate 3, figs. 5 to 8. 

 Sismondia antillarum Brown, 1914 (non Cotteau), Proc. Acad. Nat. Sci., Philadelphia, 



vol. 65, p. 601. 



The following is an extract from the original description of this 

 species : 



Species of small size, rounded, slightly oval, a little angular anteriorly; 

 upper face convex, lower face depressed, concave in the middle. Apex 

 central. Ambulacral petals relatively large, subcostulate, open at their 

 tips. Ambulacral pores very unequal, the inner ones rounded, the outer 

 narrow, oblique, and very elongate. At some distance from the border 

 of the test the pores cease to be petaloid, becoming equal, rounded, and 

 disposed in oblique pairs. They are not visible on the lower side of the 

 test. Tubercles are crowded, abundant, homogeneous. Periproct circular, 

 situated about halfway from the peristome to the posterior border of the 

 test, but a little nearer to the latter. Peristome rounded, opening in the 

 middle of the lower face in a deep depression. 



