82 FOSSIL ECHINI OF THE WEST INDIES. 



from Anguilla, and he attributes them both to the Pliocene(?), An- 

 guilla, 1 specimen, collected by J.W. Gregory in 1899; British Museum. 



Brissopsis antillarum Cotteau. 

 (Plate 14, Figures 3, 4.) 



Brissopsis antillarum Cotteau, 1875, Kongl. Sven. Vet. Akad. Handl., vol. 13, No. 6, p. 37, 

 plate 6, figs. 19 to 25. 



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

 Species of medium size, subcordiform, a little acuminate posteriorly. 

 Upper face moderately swollen, having its greatest height posteriorly. 

 The posterior end is narrow and a little obliquely truncate. Lower face 

 depressed, but having posteriorly a swelling in the plastron. The apical disk 

 is excentric anteriorly. The anterior furrow is wide, deep, extending to 

 the ambitus, and prolonged below as far as the peristome. The anterior 

 ambulacrum III is straight, with very small pores disposed in oblique 

 pairs. The paired ambulacra have the petals excavated and nearly equal, 

 but the anterior pair II and IV are widely separated, while the posterior 

 pair I and V are nearer together, and have a tendency to round themselves 

 a little on each side of the summit. Poriferous areas are wide, with oblong 

 pores, comma-like, nearly equal, scarcely open at their extremity. Inter- 

 poriferous areas are very narrow, nearly wanting. Approaching the apical 

 disk, the anterior halves of ambulacra II and IV are partly atrophied and 

 the pores are reduced to small separated pores. [Similarly in the same region 

 the posterior halves of ambulacra I and V are partly atrophied and the 

 pores correspondingly reduced.] Ventrally, the ambulacral areas form 

 wide, smooth bands; the plates are very greatly developed and the pores 

 very widely spaced. The pores are nearer together and enlarge a little 

 near the peristome. Tubercles are small dorsally, except at the apex and 

 on the borders of the anterior furrow, where they are larger; they are also 

 larger on the lower side. Peristome semicircular, excentric anteriorly, 

 but well removed from the anterior border. Periproct rounded, opening 

 at the summit of the posterior face. There are 4 genital pores; the anterior 

 pair 2 and 3 are nearer together than are the posterior pair 1 and 4. Peri- 

 petalous and subanal fascioles are narrow, sinuous, and perfectly distinct. 



Height, 20 mm., length, 47 mm., width, 38 mm. This is the measure- 

 ment of the largest of 3 specimens in Washington; it is somewhat 

 depressed, so that if not depressed, it would be a little higher. The best 

 preserved specimen is somewhat smaller and measures 20 mm. in height, 

 43.5 mm. in length, and 36 mm. in width. A young specimen which is 

 finely preserved measures 7 mm. in height, 14 mm. in length, and 11.5 

 mm. in width. All the evidence is that this young one and the largest 

 one are the specimens which were figured by Cotteau. This species 

 differs from B. jimenoi and atlantica, the only other West Indian fossil 

 species of the genus, in that the anterior paired ambulacral petals are 

 more divergent and not curved in antillarum. Cotteau cites differences 

 between antillarum and a number of European species. 



Oligocene, Anguilla formation, island of Anguilla, Guppy collection 

 ex Cleve, 3 specimens, cotypes, the originals of Cotteau's plate 6, figures 

 19 to 25, U. S. Nat. Mus. No. 115406. Crocus Bay, southwest side, 



