SYSTEMATIC DESCRIPTIONS — SPATANGINA. 71 



far anteriorly, 5 mm. from the anterior border. The plastron is wide, 

 swollen, and ornamented with tubercles in regular, close-ranked series. 

 The single known specimen of this species measures 17 mm. in height, 

 23 mm. in length, and 20 mm. in width. 



The species Agassizia inflata is near to clevei, and the specimen here 

 described was included in that species by Cotteau in his original descrip- 

 tion. Guppy made the remark, in his 1882 paper, that this was the 

 only known case in which one species of Echini occurred in both the 

 islands of St. Bartholomew and Anguilla. The species inflata differs 

 from clevei in its wider and more conical form, in its anterior curvature 

 from the apical disk to the ambitus, in its more marked furrow an- 

 teriorly, more elevated swollen plastron, and in the fact that ambulacra 

 1 1 and IV are both longer and less divergent than in clevei. 



Eocene, St. Bartholomew limestone, St. Bartholomew, Guppy collec- 

 tion ex Cleve, holotype, 1 specimen only, U. S. Nat. Mus. No. 325610. 



Agassizia clevei Cotteau. 



(Plate 12, Figures 5 to 7.) 



Agassizia clevei Cotteau (pars), 1875, Kongl. Sven. Vet. Akad. Handl., vol. 13, No. 6, p. 33, 

 plate 6, figs. 2 to 8; non 9, 10. Guppy (pars), 1882, Scientific Assoc. Trinidad, Proc., 

 part 12, p. 197. 



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



Species of small size, ovoid, rounded anteriorly, a little narrower pos- 

 teriorly; upper face very swollen, obliquely inclined anteriorly, having 

 its greatest height through the apical disk. Posterior face narrow, truncate 

 subvertically; a little reentrant. The lower face is slightly projecting, 

 depressed in front of the peristome. Apical disk excentric posteriorly, 

 anterior furrow scarcely apparent on the upper face, wholly wanting at 

 the ambitus. Anterior ambulacrum III straight, circumscribed by small 

 pores disposed in pairs. The paired ambulacra are unequal, the anterior 

 divergent, subflexuous, slightly excavated; the posterior shorter, nearly 

 superficial. Pores of the anterior paired ambulacra II and IV very un- 

 equal. The anterior half-area is reduced in all its extent to very small 

 pores, rounded, nearly microscopic, disposed in oblique pairs, forming a 

 linear series which passes beyond the petals and extends to the peristome. 

 The posterior half-area is much larger and composed of pores oblong and 

 transverse. The two halves approach one another and leave scarcely 

 place for a narrow interporiferous band. Pores of the posterior pair of 

 ambulacra I and V always equal, nearly identical in distribution to the 

 larger (or posterior) half of the anterior paired ambulacra II and IV. 

 Tubercles are crowded, abundant; unequal, most developed on the anterior 

 face and on the inframarginal region. On the lower face the interambulacral 

 plastron is covered with scaly tubercles disposed in very regular divergent 

 series. The space occupied by the posterior ambulacra, in place of being 

 smooth, is finely granular. The peristome is semicircular, labiate, near to 

 the [anterior] border. The periproct is subtransversely angular at the 

 summit of the posterior face. Apical disk compact, slightly developed, 

 with 4 genital pores, the 2 anterior much less separated than the two pos- 

 terior. Madreporite elongate, narrow, and extended to the center of the 

 apical disk, as in Prenaster. The peripetalous fasciole is narrow, sineous, 



