72 FOSSIL ECHINI OF THE WEST INDIES. 



incomplete. At some distance from the anterior ambulacrum it enlarges 

 and goes to rejoin the marginal fasciole, which is sinuous and passes under 

 the periproct in descending as far as the base of the posterior face. 



One of the two specimens of this species in Washington measures 

 13 mm. in height, 19 mm. in length, and 15 mm. in width. The second 

 specimen is of about the same size. The relatively large specimen, of 

 which Cotteau (1875) gives measurements in the last paragraph of his 

 page 33, is evidently the one from St. Bartholomew, which is here con- 

 sidered a distinct species, A. inflata. While nearly allied, these species 

 differ as set forth in the description of A. inflata. 



Oligocene, Anguilla formation, Anguilla, Guppy collection ex Cleve, 

 2 specimens, cotypes, U. S. Nat. Mus. No. 115407. Besides the Cleve 

 collection, Cotteau mentions having material from the museums of 

 Stockholm and Upsala; he does not say whether they were from An- 

 guilla or not. Southwest side of Crocus Bay, 30 to 50 feet above sea- 

 level, Anguilla, T. W. Vaughan collector, 1914, 1 specimen, U. S. Geol. 

 Sur. station, 6966. 



Genus PRENASTER Desor, 1853. 



Type species. — Prenaster alpinus Desor, 1853, Act. Soc. Helv. Sci. Nat., 

 vol. 38, p. 279 [12 of reprint]. 



Prenaster loveni Cotteau. 



(Plate 12, Figures 8, 9.) 



Prenaster loveni Cotteau, 1875, Kongl. Sven. Vet. Akad. Handl., vol. 13, No. 6, p. 34, plate 

 6, figs. 11 to 15. 



The following is an extract from the original description of this species : 



Species of medium size, elongate, ovoid, rounded anteriorly; subcarinate 

 posteriorly. The upper face is high, swollen, everywhere of about equal 

 height. Posterior face vertically subtruncate, rounded; lower face uni- 

 formly rounded. Apical disk excentric anteriorly. Anterior furrow wholly 

 wanting, even at the approach to the apical disc. Anterior ambulacrum 

 III straight, with pores disposed in pairs of separated pores. The paired 

 ambulacra are subpetaloid, slightly concave, open at their extremity, 

 unequal ; the anterior long, nearly transverse [at an angle of about 155° 

 to each other], the posterior shorter, more nearly convergent and forming an 

 acute angle [of about 55°] posteriorly. Poriferous areas are wide, composed 

 of transverse pores united by a furrow, unequal, the internal oval, the 

 external more elongate. The interporiferous areas are well developed and 

 depressed in the middle. Peristome semicircular and near the anterior 

 border. Periproct oval, opening on the posterior face. The tubercles, 

 apical disk, and fascioles are not known in this species, and it is only by 

 reason of its form, position of the ambulacra, and absence of the anterior 

 furrow that it is placed in the genus Prenaster. 



The only specimen in the collection measures 20 mm. in height, 23 mm. 

 in length, and 20 mm. in width. The periproct is high up on the posterior 

 end and is just visible from above, though not so shown in Cotteau's 

 figures. This is quite natural, for a so nearly globular specimen shows 



