SYSTEMATIC DESCRIPTIONS — SPATANGINA. 69 



Family ECHINOCORYTHH>.£ Gregory, 1900. 

 Genus CARDIASTER Forbes. 



Type species. — Spatangus excentricus Woodward, 1833, Geology of 

 Norfolk, p. 37, also [57], explanation of plate 1, fig. 5. 



Cardiaster cubensis, new species. 

 (Plate 12, Figure 1.) 



The following is a description of this species : 



Test large, low, cordiform, with a deep sulcus anteriorly, bounded by 

 a high rounded ridge on either side; posteriorly contracted to a rounded 

 end; dorsally a rounded but sloping ridge runs from the apical disk to the 

 posterior end. From this posterior sloping elevation and from the ridges 

 bounding the anterior sulcus the surface of the test slopes in a gentle incline, 

 right and left from the center to the ambitus. The ventral side is wanting, 

 but the indications are that it was at least comparatively flat. The greatest 

 height is through the apical disk, which is excentric posteriorly. The width 

 and length of the test measure alike, and the height is about but somewhat 

 more than one-third of the length. The ambulacra are non-petaloid, flush 

 with the surface of the test, except the anterior, which is in a deep groove. 

 The anterior ambulacrum III is much narrower than the other areas, but 

 widening from the apical disk, passing toward the ambitus, the ambulacral 

 plates are proportionately and actually higher than in the other areas, and 

 the two pores in each plate are small and set at an oblique angle, the lower 

 pore being the inner of each pair. Ambulacra of the anterior pair II and 

 IV from the apex, where they are narrow, widen progressively to the ambitus, 

 and present a strong, sweeping, forward curve in outline, the posterior 

 side of each of these two areas presenting the more strongly curved outline. 

 The pores of these ambulacra II and IV differ markedly on the two sides 

 of each area. Starting dorsally near the apical disk, where the pores are 

 all closely alike, being elongate and oval, and passing ventrally, the pos- 

 terior row of pores in each area becomes long drawn out and almost slit- 

 like and widely spaced. On the other hand, the pores of the anterior half 

 of each of these two areas are rounded on the outer side and elongate oval 

 on the inner side. Passing ventrally, the pores of these anterior half-areas 

 move from the anterior end of each plate gradually, until at the ambitus 

 they occupy the middle line (vertically) of the plates ; here also both pores 

 are smaller and rounded instead of larger and one elongate oval. On the 

 anterior half of these two areas II and IV, the outer pores retain an approach 

 to a circular form throughout the length of the area, but the inner series 

 elongate, though not in anything like the degree that they do on the pos- 

 terior halves of the same areas. The posterior ambulacra I and V are very 

 much shorter and narrower than the anterior pair. They widen and curve 

 forward somewhat in passing to the ambitus. The character and shape 

 of the pores is similar to those of the anterior pair, but in a very much less 

 degree. The apical disk is situated posteriorly, 35 mm. from the posterior 

 border and 56 mm. from the anterior border of the test. The plates of 

 the apical disk are in part preserved and genital 5 is absent, as is typical 

 of the genus. Oculars IV and V meet the middle line of the area, but are 

 separated from each other by genital 4, showing that it has the typical 

 apical disk characteristic of the genus. The periproct is not observable, 

 as the plates are broken away at the posterior end and nothing of the 



